Solid dosage form production

ABSTRACT

The present disclosure utilises 3D printing technology, particularly fused filament fabrication, FFF, 3D printing, in conjunction with solid and/or liquid dispensers to produce solid dosage forms, such as pharmaceutical capsules. Such solid dosage forms have a shell, which is 3D printed, and a core, which is dispensed.

INTRODUCTION

The present invention relates to a solid dosage form printing apparatus(and method for its use) in the production of solid dosage forms, suchas capsules. The invention also relates to solid dosage forms obtainableby such printing methods and apparatus, a solid dosage form package,relevant materials and printing elements (and processes for theirmanufacture), a kit of parts, a computer for controlling the relevantprinting process (and software and computer-implemented methodsconnected therewith), a system for collecting data relating to the soliddosage form production process (and databases associated therewith), andrelevant blueprints for use in the printing of solid dosage forms.

BACKGROUND

The production and consumption of medicines, nutraceuticals, and foodsupplements (collectively referred to herein as “healthcare dosageforms”), in solid dosage form (e.g. tablets, implants, etc.) is everincreasing, not least due to an increased reliance on such products bynational health services and the like in an increasinglyhealth-conscious society. Where possible, solid dosage forms tend to bemost preferred, relative to other formulations (e.g. injectable liquidformulations), due to their ease of administration (i.e. usually orally)which gives rise to better patient compliance, storability andtransportability (low space requirements and ease of packaging), highstability (longer lifetimes—less degradation). However, despite thesignificant advantages of solid dosage forms over other dosage forms,they are often more onerous to manufacture (in terms of the number ofboth ingredients and processing steps) and are generally only costeffective to produce on large scale, meaning large manufacturingfacilities with sophisticated equipment is usually required. Thesemanufacturing limitations have a detrimental impact on consumer choiceand/or the customisability of healthcare dosage forms since, forexample, it is impractical and non-cost effective to mass produce a widevariety of different dosages for a given medicament via conventionalmanufacturing techniques. Consumers (e.g. patients) and healthcareprofessionals (e.g. doctors, pharmacists) must therefore make the bestof the limited variety of dosages available, as dictated by thesuppliers rather than a consumer's need.

Since the advent of 3-dimensional (3D) printing in the early 1980s, anumber of researchers have attempted to make viable use of 3D printingtechnology to fabricate healthcare solid dosage forms. For instance, forwell over a decade, MIT and Therics, Inc. have collaborated in thedevelopment of viable pill printing machines which utilise 3D printersto print solid pharmaceutical dosage forms in situ. The technology formspills via a multi-layered 3D printing process involving precise printingof doses of a liquid drug solution onto thin layers of fine powderbefore further layers are then applied (e.g. further powder, binder,etc.). Examples of such processes are disclosed in earlier publications,such as WO95/11007 (MASSACHUSETTS INSTITUTE OF TECHNOLOGY) andWO03/092633 (THERICS, INC.), which describe inter alia the production ofsolid dosage forms having various structures and drug release profiles.However, regulatory approval (e.g. by the FDA or MHRA) for such 3D drugprinting systems still remains elusive, and for the time being they aresuitable only for low dose drug products, partly owing to the limitedsolubility of many drugs within the relevant ink solutions. As such,patient choice would still be very limited, as would the options of adoctor or pharmacist in providing specially-tailored treatments.Furthermore, resolution and shape of the solid dosage form still remainsan issue. However, a particular issue with prior art 3D printing systemssuch as these is that the large number of different ingredients (andthus different printing cartridges etc.) needed to produce viable dosageforms imparts a high degree of complexity, user-unfriendliness, which inturn increases the likelihood of manufacturing errors, machine breakdownand malfunction, quality control variation, and regulatory viability(i.e. the FDA is less likely to approve drug printing systems which areprone to too many variables that may impact on the quality of the drugproduct). A further issue is the poor stability of some drug substances,especially in liquid ink formulations. This can severely limit theshelf-life of the drug source, thus posing large regulatory and costissues.

Efforts have also been made to develop powder-based 3D printing in orderto produce solid dosage forms with different drug release profiles.However, such techniques suffer from various shortcomings, including:the need to dry the powders, prolonged processing times, weak tabletswhich readily disintegrate, poor resolution and poor shape control, andlimited control of drug release profiles.

The Applicants previous work outlined in WO2016/038356 (University ofCentral Lancashire), which primarily focussed on the use in 3D printingof drug-containing FDM filaments, aims to solve one or more of theaforesaid problems. However, there remains a need for alternativesolutions. Though WO2016/038356 provides various innovative options forreducing the melting/softening temperatures of the drug-containingfilaments, for some drugs (especially those with low decompositiontemperatures) the filament printing temperatures can still be too high,and decomposition can occur during printing. Furthermore, the technologydescribed in WO2016/038356 deploys significant proportions ofthermoplastics in the formation of dosage forms, which can beundesirable and limit maximum drug-loadings. It is desirable to extendthe scope of applicability of the 3D-printing technology described inWO2016/038356, for instance by allowing for a broader range of inputmaterials. For example, the 3D printing of solid dosage forms containingpolypeptides, proteins and other biopharmaceuticals is seen asdesirable, notwithstanding the stability challenges these inherit. It isfurthermore desirable to be able to provide such solid dosage forms withimmediate, enteric, and/or extended release properties.

It is therefore an object of the invention to provide improved and/oralternative methods of producing solid dosage forms, and to suitablesolve at least one problem inherent in the prior art.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is providedan apparatus for preparing (or printing) a solid dosage form, theapparatus comprising:

-   -   a 3D printer; and    -   a build platform upon which the solid dosage form is printable        (i.e. upon which the solid dosage form may be built); and    -   a computer for controlling the 3D printer and optionally also        the build platform;    -   wherein the apparatus (or 3D printer) comprises or is otherwise        associated with:        -   a structural printing nozzle for printing a pre-defined            three-dimensional shell, comprising a shell composition,            onto the build platform; and        -   a non-structural dispenser for unstructured dispensing of a            core composition (which is suitably a liquid and/or a            particulate solid) into the shell.            (wherein the FFF 3D printer is suitably operable via the            computer, suitably a computer running pursuant to specialist            solid dosage form printing software, and optionally also to            one or more databases, to print the solid dosage form upon            the build platform. Any one or more of the build platform,            core composition, shell composition, and/or computer, and/or            any part thereof, may suitably be integrated within or form            a part of the FFF 3D printer).

According to a further aspect of the present invention there is provideda method of preparing (or printing) a solid dosage form, the methodcomprising:

-   -   printing a pre-defined three-dimensional open shell, comprising        a shell composition (or precursor thereof), onto a build        platform;    -   dispensing a core composition (or precursor thereof) into the        open shell to produce an open core-containing shell;    -   closing the open core-containing shell by printing a closure,        optionally comprising the shell composition (or precursor        thereof), thereupon.

According to a further aspect of the present invention, there isprovided a computer for operating an apparatus for preparing (orprinting) a solid dosage form as defined herein, wherein the computercomprises:

an interface connecting or enabling connection of (whether wirelessly orwired) the computer to or within a solid dosage form printing apparatus(suitably to allow the computer to control and/or operate theaforesaid);

wherein the computer runs pursuant to solid dosage form printingsoftware (and optionally also to one or more databases), whichconfigures the computer to carry out the steps of:

-   -   i) obtaining information (e.g. through manual user input or via        one or more databases, optionally in response to a user-inputted        reference, such as a patient's name) regarding one or more        parameters pertaining to the solid dosage form to be printed        (e.g. the active ingredient, active loading/dose, shape, release        profile, etc.);    -   ii) calculating the mass and/or volume of the solid dosage form        to be printed based on the information obtained in step (i);    -   iii) controlling printing of and relative proportions of        ingredients within (i.e. make up of the solid dosage form) the        solid dosage form by, on the basis of the information obtained        in step (i) and calculations performed in step (ii):        -   a. controlling printing, deposition, and/or extrusion, of a            shell composition (or precursor thereof wherever chemical            transformations thereof occur after printing, deposition,            and/or extrusion) and a core composition (or precursor            thereof wherever chemical transformations thereof occur            after printing, deposition, and/or extrusion);        -   b. optionally controlling printing, deposition, and/or            extrusion, of one or more further printing compositions;        -   c. optionally controlling performance of one or more further            processing steps.

According to a further aspect of the present invention, there isprovided a computer-implemented method of operating an apparatus forpreparing (or printing) a solid dosage form, or a computer-implementedmethod of preparing (or printing) a solid dosage form, the methodcomprising:

operating a computer (with suitable data connections to the relevantprinting apparatus, be them wired or wireless) running pursuant to soliddosage form printing software (and optionally also to one or moredatabases) to:

-   -   i) obtain information (e.g. through manual user input or via one        or more databases, optionally in response to a user-inputted        reference, such as a patient's name) regarding one or more        parameters pertaining to the solid dosage form to be printed        (e.g. the active ingredient, active loading/dose, shape, release        profile, shape, colour, etc.);    -   ii) calculate the mass and/or volume of the solid dosage form to        be printed based on the information obtained in step (i);    -   iii) control printing of and relative proportions of ingredients        within (i.e. make up of the solid dosage form) the solid dosage        form by, on the basis of the information obtained in step (i)        and calculations performed in step (ii):        -   a. controlling printing, deposition, and/or extrusion, of a            shell composition (or precursor thereof wherever chemical            transformations thereof occur after printing, deposition,            and/or extrusion) and a core composition (or precursor            thereof wherever chemical transformations thereof occur            after printing, deposition, and/or extrusion);        -   b. optionally controlling printing, deposition, and/or            extrusion, of one or more further printing compositions;

c. optionally controlling performance of one or more further processingsteps.

According to a further aspect of the present invention, there isprovided a computer program, comprising solid dosage form printingsoftware code for performing the computer-implemented method definedherein when the computer program is run on a computer.

According to a further aspect of the present invention, there isprovided a blueprint (or computer-readable code) for preparing (orprinting) a solid dosage form as defined herein, the blueprintcomprising information regarding one or more parameters pertaining tothe solid dosage form to be printed (e.g. the active ingredient, activeloading/dose, shape, release profile, shape, colour, etc).

According to a further aspect of the present invention, there isprovided a computer-readable medium comprising solid dosage formprinting software code executable to cause a computer to perform thecomputer-implemented method defined herein when the software code isexecuted on a computer.

According to a further aspect of the present invention, there isprovided a computer-readable medium comprising a blueprint for preparing(or printing) a solid dosage form as defined herein.

According to a further aspect of the present invention there is provideda solid dosage form obtainable by, obtained by, or directly obtained bythe method of preparing (or printing) a solid dosage form as definedherein.

According to a further aspect of the present invention there is provideda solid dosage form comprising a core and a three-dimensional shellsurrounding the core;

wherein:

-   -   the shell comprises a shell composition, the shell composition        suitably comprising (or formed from) a 3D printing composition        (e.g. a fused filament fabrication composition), wherein the        shell composition is suitably (structurally) solid; and    -   the core comprises a core composition, the core composition        comprising an active ingredient, suitably a pharmaceutically,        nutraceutically, or food-supplement active ingredient, wherein        the core composition (suitably a solid, liquid, or gel) is        suitably contained by the shell.

According to a further aspect of the invention, there is provided amethod of producing a solid dosage form package, the method comprisingpackaging one or more solid dosage forms as defined herein, wherein theone or more solid dosage forms are optionally the same or different.

According to a further aspect of the invention, there is provided asolid dosage form package, obtainable by, obtained by, or directlyobtained by the method of producing a solid dosage form package asdefined herein.

According to a further aspect of the invention, there is provided asolid dosage form package, comprising one or more solid dosage forms, asdefined herein, within a packaging.

According to a further aspect of the invention, there is provided a kitof parts comprising a shell composition (suitably as defined herein) anda core composition (suitably as defined herein).

Methods, and judicious variations thereof, of using an apparatus may beapplied (as appropriate) to any of the apparatuses defined herein.

Any features, including optional, suitable, and preferred features,described in relation to any particular aspect of the invention may alsobe features, including optional, suitable and preferred features, of anyother aspect of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, and to show how embodimentsof the same are put into effect, reference is now made, by way ofexample, to the following diagrammatic drawings, in which:

FIG. 1 is a schematic diagram of a dual FDM 3D printer adapted toaccommodate a) a liquid dispenser or b) a powder/granule/pelletsdispenser in combination with FDM 3D printer head.

FIG. 2 shows a dual FDM 3D printer adapted to accommodate a liquiddispenser in combination with FDM 3D printer head and furtherillustrates, by way connecting arrows between an image of a basiccore-shell structure and the relevant print, which components areconfigured to print each part of a core-shell structure.

FIG. 3 shows a portion of the dual FDM 3D printer adapted to accommodatea liquid dispenser (right) in combination with FDM 3D printer head(left).

FIG. 4 is a graph showing a time-course in vitro drug release profilefor of dipyridamole release from Eudragit L based capsules filled withdrug suspension.

FIG. 5 shows a calibration curve for the actual volume againsttheoretical volume for single head printing using (a) 0.25, (b) 0.41 or(c) 0.84 mm nozzle sizes.

FIG. 6 shows a calibration curve for actual volume against theoreticalvolume for dual printing head using (a) 0.25, (b) 0.41 or (c) 0.84 mmnozzle size.

FIG. 7 shows the relationship between actual volumes from single anddual printing from (a) 0.25, (b) 0.41 or (c) 0.84 mm nozzle.

FIG. 8 shows in vitro release of dipyridamole from Eudragit L basedcapsule filled with drug suspension with different loading.

FIG. 9 shows the release profile of dipyridamole from immediate releaseshell.

FIG. 10 shows a rendered image and photograph of a liquid capsule madeof an immediate release shell (Eudragit E shell) and filled withmicrosuspension of dipyridamole (1.5% w/v).

FIG. 11 is a chart showing the impact of single and alternating printingmodes from the liquid dispenser using a 2 mL syringe.

FIG. 12 is a chart showing the impact of single and alternating printingmodes from the liquid dispenser using a 10 mL syringe.

FIG. 13 is a graph showing the linear relationship between theoreticalvolumes calculated volumes based on volume of design and the actual doseachieved via 3D printing.

FIG. 14 shows in vitro immediate release profiles for dypiridamolesuspension from 3D printed liquid Eudragit EPO capsule using USP II withdifferent core volumes in gastric media (pH 1.2).

FIG. 15 shows SEM images of the top of shell produced by two differentfilling modes: a) concentric Filing and b) rectangular filling.

FIG. 16 shows release profiles for theophylline-cored-capsules producedwith immediate release shells containing Eudragit EPO.

FIG. 17 shows release profiles for theophylline-cored-capsules producedwith extended release shells containing Eudragit RL 100.

FIG. 18 shows a calibration curve for the powder dispenser (pinchvalve).

FIG. 19 shows an in vitro dissolution profile, in gastric medium (0.1 MHCl) USP II dissolution test, for an immediate release 3D printedcapsule filled with theophylline granules.

FIG. 20 shows an in vitro dissolution profile, in gastric medium (0.1 MHCl), of 3D printed delayed release entire capsule filled withtheophylline granules.

DETAILED DESCRIPTION OF THE INVENTION Definitions

Unless otherwise stated, the following terms used in the specificationand claims have the following meanings set out below.

Throughout the description and claims of this specification, the words“comprise” and “contain” and variations of them mean “including but notlimited to”, and they are not intended to (and do not) exclude othermoieties, additives, components, integers or steps. Throughout thedescription and claims of this specification, the singular encompassesthe plural unless the context otherwise requires. In particular, wherethe indefinite article is used, the specification is to be understood ascontemplating plurality as well as singularity, unless the contextrequires otherwise.

Features, integers, characteristics, compounds, chemical moieties orgroups described in conjunction with a particular aspect, embodiment orexample of the invention are to be understood to be applicable to anyother aspect, embodiment or example described herein unless incompatibletherewith. All of the features disclosed in this specification(including any accompanying claims, abstract and drawings), and/or allof the steps of any method or process so disclosed, may be combined inany combination, except combinations where at least some of suchfeatures and/or steps are mutually exclusive. The invention is notrestricted to the details of any foregoing embodiments. The inventionextends to any novel one, or any novel combination, of the featuresdisclosed in this specification (including any accompanying claims,abstract and drawings), or to any novel one, or any novel combination,of the steps of any method or process so disclosed.

The reader's attention is directed to all papers and documents which arefiled concurrently with or previous to this specification in connectionwith this application and which are open to public inspection with thisspecification, and the contents of all such papers and documents areincorporated herein by reference.

For the avoidance of doubt, it is hereby stated that the informationdisclosed earlier in this specification under the heading “Background”is relevant to the invention and is to be read as part of the disclosureof the invention.

Unless stated otherwise, any reference herein to the term “melt” (or itsderivatives), especially in the context of melting filaments, suitablyincludes a glass transition or softening of a given material, suitablyto allow extrusions thereof (e.g. through a nozzle). However, the term“melt” in the context of a defined “melting point” of a substance is asdefined as per the art—a phase transition from solid to liquid.

Herein, references to “glass transition temperature” or “T_(g)” suitablyrefers to the temperature at which a material softens (e.g. to allowextrusion thereof). Suitably, glass transition temperatures (Tg) ofmaterials described herein may be determined by a standard test method,suitably using dynamic mechanical analysis—a suitable test includes thetesting protocol defined by ASTM E1640. Differential Scanningcalorimetry (DSC) may also be utilised. For instance, glass transitiontemperatures may be discerned using the protocols set forth in ASTME1356 and ASTM D7426. It will be understood by those skilled in the artthat references herein to a particular material's glass transitiontemperature falling within a certain temperature range is intended tomean that at least one glass transition temperature of said material(which may or may not have multiple glass transition temperatures) fallswithin said temperature range. Suitably unqualified references to a“glass transition temperature” means at least one, suitably means thelowest glass transition temperature, and may suitably mean the glasstransition temperature which absorbs the most thermal energy (or is mostendothermic). The key, which is self-evident to those skilled in theart, is that sufficient softening of said material occurs under aparticular set of circumstances (e.g. at the printing nozzle, where afilament needs to be softened in order to be extruded during theprinting process, after which resolidification or rehardening may takeplace).

Unless stated otherwise, the term “viscosity” as used herein refers to aviscosity determined by means of a Brookfield viscometer (UL adapter/30rpm/20° C.) in accordance with testing protocols defined by Ph. Eur.2.2.10 or USP<912> method II.

Unless stated otherwise, any reference herein to an “average” value isintended to relate to the mean value.

Where a composition is said to comprise a plurality of stipulatedingredients (optionally in stipulated amounts of concentrations), saidcomposition may optionally include additional ingredients other thanthose stipulated. However, in certain embodiments, a composition said tocomprise a plurality of stipulated ingredients may in fact consistessentially of or consist of all the stipulated ingredients.

Herein, where a composition is said to “consists essentially of” aparticular component, said composition suitably comprises at least 70 wt% of said component, suitably at least 90 wt % thereof, suitably atleast 95 wt % thereof, most suitably at least 99 wt % thereof. Suitably,a composition said to “consist essentially of” a particular componentconsists of said component save for one or more trace impurities.

Where the quantity or concentration of a particular component of a givencomposition is specified as a weight percentage (wt % or % w/w), saidweight percentage refers to the percentage of said component by weightrelative to the total weight of the composition as a whole. It will beunderstood by those skilled in the art that the sum of weightpercentages of all components of a composition will total 100 wt %.However, where not all components are listed (e.g. where compositionsare said to “comprise” one or more particular components), the weightpercentage balance may optionally be made up to 100 wt % by unspecifiedingredients (e.g. a diluent, such as water, or other non-essentially butsuitable additives).

Herein, unless stated otherwise, the term “parts” (e.g. parts by weight,pbw) when used in relation to multiple ingredients/components, refers torelative ratios between said multiple ingredients/components. Expressingmolar or weight ratios of two, three or more components gives rise tothe same effect (e.g. a molar ratio of x, y, and z is x₁:y₁:z₁respectively, or a range x₁-x₂:y₂:z₁-z₂). Though in many embodiments theamounts of individual components within a composition may be given as a“wt %” value, in alternative embodiments any or all such wt % values maybe converted to parts by weight (or relative ratios) to define amulti-component composition. This is so because the relative ratiosbetween components is often more important than the absoluteconcentrations thereof in the liquid pharmaceutical compositions of theinvention. Where a composition comprising multiple ingredients isdescribed in terms of parts by weight alone (i.e. to indicate onlyrelative ratios of ingredients), it is not necessary to stipulate theabsolute amounts or concentrations of said ingredients (whether in totoor individually) because the advantages of the invention can stem fromthe relative ratios of the respective ingredients rather than theirabsolute quantities or concentrations. However, in certain embodiments,such compositions consists essentially of or consist of the stipulatedingredients and a diluents (e.g. water).

The term “mole percent” (i.e. mol %) is well understood by those skilledin the art, and the mol % of a particular constituent means the amountof the particular constituent (expressed in moles) divided by the totalamount of all constituents (including the particular constituent)converted into a percentage (i.e. by multiplying by 100). The concept ofmol % is directly related to mole fraction.

The term “substantially free”, when used in relation to a givencomponent of a composition (e.g. “a liquid pharmaceutical compositionsubstantially free of compound X”), refers to a composition to whichessentially none of said component has been added. When a composition is“substantially free” of a given component, said composition suitablycomprises no more than 0.001 wt % of said component, suitably no morethan 0.0001 wt % of said component, suitably no more than 0.00001 wt %,suitably no more than 0.000001 wt %, suitably no more than 0.0000001 wt% thereof, most suitably no more than 0.0001 parts per billion (byweight).

The term “entirely free”, when used in relation to a given component ofa composition (e.g. “a liquid pharmaceutical composition entirely freeof compound X”), refers to a composition containing none of saidcomponent.

Suitably, unless stated otherwise, where reference is made to aparameter (e.g. pH, pKa, etc.) or state of a material (e.g. liquid, gas,etc.) which may depend on pressure and/or temperature, suitably in theabsence of further clarification such a reference refers to saidparameter at standard ambient temperature and pressure (SATP). SATP is atemperature of 298.15 K (25° C., 77° F.) and an absolute pressure of 100kPa (14.504 psi, 0.987 atm).

Herein, the term “particle size” or “pore size” refers respectively tothe length of the longest dimension of a given particle or pore.Particle and pore sizes may be measured using methods well known in theart, including a laser particle size analyser and/or electronmicroscopes (e.g. transmission electron microscope, TEM, or scanningelectron microscope, SEM).

General Points and Advantages Relating to the Invention

The present invention deploys 3D printing technology to produce soliddosage forms, particularly pharmaceutical dosage forms, though theskilled person will readily appreciate that the principles of theinvention are readily applicable to nutraceuticals and food supplements.The 3D printing apparatuses of the invention uniquely juxtapose standard3D printing components with one or more non-printing dispensers so thattogether they are operable to print a solid 3D shell that encapsulates acore composition that has been dispensed into the shell in a non-printedmanner. Standard 3D printing components may include printing nozzles,preferably comprising at least one non-powder-based printing nozzle suchas those used in fused filament fabrication (FFF) printing, along withany relevant conveying and/or heating means that allows the printingcompositions to be printed onto a surface, typically in asequential-layered fashion. Non-printing dispensers may include anydispensing means that allows liquids and/or solids to be dispensedtherefrom (suitably in bulk as opposed to a sequential-layered fashion)into a solid dosage form-sized containment vessel. This may, forexample, include syringes (which may dispense liquids, emulsions,dispersions, suspensions, nanosuspensions, or even powdered solids),valve-operated and optionally pressurized hoppers (which may dispensesolids or liquids), and the like. Importantly, the 3D shell is printed(generally discernible by a printed layered structure) whilst the innercore is not (and is instead a bulk mass of dispensed material with nodiscernible layered structure).

Suitably, concentric filling may be used to form the shell.

In general, printing of solid dosage forms of the invention may beachieved by initially printing a partial shell before dispensingthereinto a core composition (generally a free flowing liquid, solid, orsuspension), before eventually closing the partial shell by printing aclosure thereupon to fully encapsulate the core composition within. Inthis manner, the partial shell can serve as a transient yet structurallystable open container for the core composition before it is finallyclosed to allow the solid dosage forms to be further manipulated andpackaged without the core composition leaking. The encapsulating shellsuitably also serves to preserve the chemical integrity of the corecomposition within.

The methods of the invention, especially where the standard 3Dcomponents comprise at least one non-powder-based printing nozzle,overcome many of the shortcomings of the powder-based 3D printingtechniques of the prior art. For instance, the invention allows for theformation of strong, well-defined, high-resolution shell structureswhich can provide secure solid containment for powders (or indeedliquids) within. Such an approach avoids the need for long drying timeswhich characterise inefficient powder-printing-based processes.

It will be appreciated, by those skilled in the art, that various wellknown methods of 3D-printing may be deployed to form a solid shell, andthat indeed a mixture of such methods may be used where appropriate orbeneficial. Though the present disclosure focuses on FFF/FDM methods of3D printing (i.e. with filaments), which are effective and low cost, theprinciples underlying the invention are more broadly applicable.

Furthermore, the methods of the invention overcome many of theshortcomings associated with FFF-based printing of solid dosage forms.For example, the invention allows the benefits of FFF-printing to beenjoyed in the printing of the 3D-shell structure, whilst mitigatingagainst its disadvantages through dispensing potentially-thermosensitivecore materials in a fashion that does not necessitate the application ofheat or the dilution of actives (e.g. in FFF filaments). As such,high-loadings of thermosensitive active ingredients can be achieved inthe solids dosage forms of the invention. This also unlocks theadvantages of 3D printing technologies in the realm ofbiopharmaceuticals, such as those comprising antibodies, polypeptides,glycopeptides, and the like.

Solid dosage forms of the invention can thus be produced “on-demand”,and in an individualised and customised manner to suit the needs ofparticular patients, thereby avoiding certain undesirable medicalcompromises (e.g. patients receiving imperfect dosages due to thelimited range of sizes of mass-produced dosage forms on offer).Separating the active ingredients from the 3D-structure-formingmaterials allows dosage forms to be made in a range of shapes and sizesbecause fewer limitations (such as those otherwise imparted by thepresence of thermosensitive active ingredients) are imposed during the3D-structure forming events.

The invention broadens the applicability of 3D printing to a wider rangeof physical forms, allowing active ingredients to reside in solid and/orliquid compositions as appropriate for the active in question.

Though chemical and physical compatibilities between the core and theshell must be considered when developing durable solid dosage forms, thedetachment of the processes forming each affords better opportunities tomaximise such compatibility.

It is expected that the present invention will make a significantcontribution to the art in terms of the production, dispensing, andconsumption of pharmaceutical products, and this will have positivehealth impacts for all concerned.

Solid Dosage Form Printing Apparatus and Associate Equipment andSoftware

The present invention provides an apparatus for preparing (or printing)a solid dosage form, suitably as defined herein. The apparatus issuitably operable to form a solid dosage form (e.g. capsule) via acombination of 3D-printing (suitably layer-by-layer), in particular toproduce a 3D shell, and non-printed dispensing of active-containingmaterials, in particular to produce a core within the 3D shell. As such,the apparatus suitably comprises one or more printing nozzles forprinting the 3D shell and one or more dispensers for dispensing coreingredients. The, or at least some of, the 3D-printing performed byapparatuses of the invention suitably involves fused filamentfabrication (FFF) printing using printing filaments comprising aparticular filament composition, generally containing thermoplastics.FFF printing is particularly preferred for forming the shell. Thereforesuitably the apparatus employs pre-fabricated filament(s) that areselectively extruded and deposited in a layer-by-layer printing processto produce a shell. The, or at least some, of the non-printed dispensingof active-containing materials (e.g. within a core composition) suitablyinvolves bulk dispensing of a flowable (e.g. fluid) material, suitablyin a metered (i.e. precisely dosed) manner. The apparatus may suitablycomprise one or more conveyors to convey relevant materials to anappropriate nozzle or dispenser.

The apparatus suitably comprises a fused filament fabrication3-dimensional printer (an FFF 3D printer). Such printers are oftenreferred to as fabrication deposition Modelling™ (FDM) 3D printers.

The apparatus suitably comprises a build platform (or built plate) uponwhich the solid dosage form is printable (i.e. upon which the soliddosage form may be built). The build platform suitably provides a(substantially flat) surface which supports the solid dosage formthroughout the printing process. In a particular embodiment, the buildplatform comprises a surface, tape layer (i.e. a layer of tape at thesurface) or surface coating which promotes adhesion of the solid dosageform to the build platform during the printing process (i.e. promotingadhesion of a first layer of the solid dosage form to be printed uponthe build plate, suitably after the first layer hardens upon cooling),though suitably the solid dosage form is (readily) removable from thebuild platform following its production.

Suitably, the apparatus comprises a computer interface (whether forwired or wireless connection to a computer operable to control the FFF3D printer or printing apparatus).

The apparatus suitably comprises a computer for controlling the FFF 3Dprinter. The computer may optionally control the build platform (e.g.its position, height, etc.).

Suitably, the apparatus comprises a structural printing nozzle forprinting a pre-defined three-dimensional shell onto a build platform.Such a structural printing nozzle is suitably characterised by anextrusion nozzle through and from which a filament (or part thereof) canbe extruded, suitably a filament comprising a shell composition(suitably as defined herein) or a precursor thereof. Such a structuralprinting nozzle is suitably a part of the 3D printer.

Suitably, the apparatus comprises a non-structural dispenser. Thenon-structural dispenser is suitably a vessel from which a corecomposition, or precursor thereof, may be dispensed. In contrast to thestructural printing nozzle, the non-structural dispenser suitablydispenses a core composition (or precursor thereof) in an unstructuredfashion. Suitably the non-structural dispenser is configured orotherwise operable to dispense core composition (or a precursor thereof)into the 3D shell printed via the structural printing nozzle. Thenon-structural dispenser may be a part of the 3D printer, or may beexternal thereto (e.g. at another station or module within the apparatusas a whole).

The apparatus of the invention may comprise one or more othercomponents, optionally printing or dispensing components for printing ordispensing other materials intended to form a part of the solid dosageform. For example, the solid dosage form may comprise multiple shells.The solid dosage form may comprise multiple different core compositions.The shell of the solid dosage form may comprise on its internal surfacea compatibility layer comprising a substance or composition that eitherincreases compatibility between the core and shell or otherwisemaintains a (substantial) separation between the core and shell.

Structural Printing Nozzle(s)

Suitably the apparatus or 3D printer of the invention comprises one ormore extrusion nozzles through and from which a filament (or partthereof) can be extruded, at least one of which is a structural printingnozzle as defined herein. References herein to nozzles and/orcharacteristics thereof, including optional characteristics thereof, aresuitably applicable to the structural printing nozzle(s).

Suitably the or each extrusion nozzle may be a heated extrusion nozzle,suitably a heated extrusion nozzle with a variable temperature control(e.g. to allow the extrusion nozzle to be selectively heated at adesired temperature). As such, the apparatus may comprise an extrusionnozzle heating element, suitably for heating the extrusion nozzle tomelt (or otherwise liquidise) the or part of the relevant filament.Suitably, the apparatus may comprise a plurality of the aforementionedextrusion nozzles, each of which may be assigned to one or morefilaments. The printing apparatus may comprise one or more extrusionnozzle heating elements associated with the or each extrusion nozzle,suitably for heating the extrusion nozzle to melt (or otherwiseliquidise) the or part of the relevant filament. Suitably, the apparatusmay comprise a plurality of the aforementioned extrusion nozzles, eachof which may be assigned to one or more filaments.

The temperature of the nozzle(s) are suitably computer-controlled.Suitably, the nozzle(s) are configured to operate at temperaturesbetween 60 and 350° C., suitably between 80 and 300° C., more suitablybetween 100 and 220° C., suitably between 120 and 190° C.

Suitably each extrusion nozzle comprises an input opening (into which afilament is fed) and an output opening (out of which molten filament isdeposited). The output opening is suitably smaller than the inputopening. The input opening is suitably dimensioned to receive acorresponding filament therethrough. Suitably the input opening has adiameter of 1.0 to 2.5 mm, more suitably 1.5 to 2.0 mm, most preferablyabout 1.75 mm. The output opening is suitably dimensioned for theproperties of the corresponding filament to allow molten filament to bedeposited therefrom (e.g. onto a build platform). Suitably the outputopening has a diameter of 50 to 400 μm, more suitably 100 to 300 μm,more suitably 150 to 250 μm, most suitably about 200 μm. In anembodiment, the nozzle has an output opening with a diameter between 200and 500 μm.

Suitably the or each nozzle may be movable (suitably in an automatedfashion or in a manner controlled by a computer or by the printer underinstruction from the computer) to extrude filament at differentlocations upon the build platform (or upon the partially formed soliddosage form printed thereon). The nozzle may be moveable in any or allof the X, Y, and Z direction, though in some embodiments (e.g. where thebuild platform is movable in the Z direction, i.e. up and down relativeto the nozzle) it is constrained to move in only X and Y directions.

Suitably the or each extrude nozzle is operable to move at a speed ofbetween 50 and 150 mm/s whilst extruding (i.e. when the nozzle is“on”—this may be the nozzle extrusion speed), more suitably between 70and 110 mm/s, more suitably between 80 and 100 mm/s. Suitably the oreach extrude nozzle is operable to move at a speed of between 100 and200 mm/s when not extruding (i.e. when the nozzle is “off”—this may bethe nozzle travelling speed), more suitably between 120 and 180 mm/s,more suitably between 140 and 160 mm/s.

It will be understood by those skilled in the art that the, each, or anynozzle may be adapted to suit the properties a corresponding filamentconfigured to print thereto. The nozzle properties/design and filamentproperties/composition suitably complement one another so as tofacilitate controlled extrusion of said filament (be it continuous orintermittent, e.g. where more than one filament is used in the printingof a solid dosage form), suitably without any nozzle blockages orimpedance, and suitably without any unacceptable degradation ofingredients within the filament during the printing process.

Suitably, the apparatus comprises a conveyor for conveying the printingfilament and any optional one or more further printing filaments toand/or through the at least one extrusion nozzle. Suitably the conveyorgrips the relevant filament and feeds it through itself towards and/orthrough the relevant extrusion nozzle. Suitably the conveyor iscontrolled to deliver the relevant filament at a rate and/or atintervals suitable to provide the desired solid dosage form. Theconveyor, or a part thereof (e.g. “a feeder”) (preferably a part enroute to the extrusion nozzle) may be heated, suitably via a heatingelement associated therewith, optionally a separate and/or separatelycontrollable heating element from any heating elements associated withthe extrusion nozzle. Where the apparatus comprises more than onenozzle, suitably the apparatus comprises more than one feeder, oneassociated with each extrusion nozzle.

Non-Structural Dispenser(s)

The apparatuses of the present invention suitably comprise one or morenon-structural dispensers, most suitably one for each core compositionhandled by the apparatus. Suitably the non-structural dispenser(s) areoperable to dispense liquids (whether or not said liquids containparticulate matter) or particulate solids.

According to an aspect of the present invention there is provided anon-structural dispenser comprising mounting elements which allow thenon-structural dispenser to be mounted within an apparatus, as definedherein, or more suitably a 3D printer as defined herein. In someembodiments, the non-structural dispenser may be or comprises acore-dispensing cartridge, which cartridge is suitably pre-loaded with aparticular core composition (or precursor thereof) intended fordispensing. As such, the non-structural dispenser may suitably comprisea core composition or a precursor thereof.

The or each non-structural dispenser suitably comprises a container,suitably a sealed or sealable container, and an outlet through which acore composition (or precursor thereof) may be dispense. Suitably theoutlet is characterised by a tubular structure (e.g. needle, tube, orpipe), suitably a substantially rigid tubular structure, suitably atubular structure having a bore size less than the maximum dimension ofthe solid dosage form to be produced—this allows for increased precisionwhen dispensing.

The non-structural dispenser may comprise or be otherwise connectable toa pressurizing element. Such a pressurize element (e.g. a syringepiston) may facilitate dispensing, especially in a metered fashion.Various pressurizing elements may be used, such a plungers/pistons,screws (e.g. Archimedes crews) and such like.

The non-structural dispenser, especially an outlet thereof, may compriseor be otherwise connectable to a valve, suitably a one-way valve, whichis operable (suitably electronically, suitably under the control of acomputer running pursuant to appropriate software) to open and close toallow a core composition within the dispenser to be selectivelydispensed. In certain embodiments, such a valve may be deployed incombination with a pressurizing element. Suitably both the valve andpressurizing element may be computer-operated to dispense a metered doseof a core composition (or precursor thereof) residing within thedispenser.

Suitably the non-structural dispenser is operable to dispense individualor multiple doses of core composition (or precursor thereof) in ametered manner. Suitably the non-structural dispenser comprises or isotherwise associated with a quantifying component for measuring aquantity of core composition (or precursor) to be dispensed. Dispensingmay, for instance, be gravimetric and/or volumetric. Suitably theapparatus of the invention is operable under computer control tocoordinate metered dispensing of each dose of core composition (orprecursor thereof) with the printing of the shell(s). As such, thestructural printing nozzle(s) and non-structural dispenser(s) suitablyfunction in a coordinated and complementary manner under the control ofthe same computer and/or computer program. However, in some embodiments,the apparatus of the invention may conceivably comprise multiple workstations, including for example: a partial shell printing station, acore dispensing station, and a shell closure station. In suchembodiments, a plurality of partial shells may be printed before beingconveyed to the core dispensing station, at which point the partialshells are “filled” with core composition (or precursor thereof).Thereafter, the multiplicity of “filled” partial shells may be conveyedto a closure station which completes the solid dosage form, or at leastcompletes the core-shell arrangement which may then proceed to furtherprocessing.

Suitably the non-structural dispenser is either unheated or is otherwiseassociated with a temperature control element that maintains thenon-structural dispenser (and suitably also its contents) at atemperature at or below 90° C., suitably at or below 60° C., suitably ator below 50° C., suitably at or below 40° C., more suitably at or below30° C., suitably at or above 0° C., suitably at or above 10° C. Such atemperature control element may be a thermocouple.

The non-structural dispenser may comprise insulation, such as anexternal insulation layer, to defend the non-structural dispenser and/orits contents against over-heating caused by neighbouring componentsduring operation of the apparatus of the invention.

Suitable internal coatings may be deployed at the outlet of thedispenser to mitigate blocking, whether the dispenser is designed todispense solids, liquids, or liquid-suspensions.

The non-structural dispenser may be operable to dispense solids,particular particulate solids such as powders.

The non-structural dispenser may be operable to dispense liquids,particular solutions, but also dispersions (e.g. colloidal dispersion),emulsions, and even suspensions (e.g. nanosuspensions).

In some embodiments, the non-structural dispenser may dispense a liquidcore composition precursor that ultimately forms a solid or gelled corecomposition within the solid dosage form. Likewise, the non-structuraldispenser may dispense a solid core composition precursor thatultimately forms a liquid or gelled core composition within the soliddosage form. In such embodiments, the core composition precursorsuitably undergoes a chemical and/or physical transformation after (oreven during) dispensing. Such a transformation may be induced in anumber of ways, discussed below in relation to methods of using thepresent apparatus.

In some embodiments, the non-structural dispenser comprises or isotherwise associated with one or more further dispenser(s) which areoperable, suitably in conjunction with the aforementioned non-structuraldispenser, to cause mixing of the core composition precursor with one ormore core reactants or extra core composition precursors during orfollowing dispensation thereof. For example, one or more corecomposition precursors and/or reactants may be caused to pre-mix in amixing chamber during their dispensation, or one or more compositionprecursors and/or reactants may be dispensed sequentially into the sametarget (i.e. into the same partial shell).

Solid Non-Structural Dispensers

The non-structural dispenser may be or otherwise comprise any suitablesolid dispensing apparatus. Various solid dispensing apparatuses areknown in the art. The core composition (or precursor thereof) fordispensing by the apparatuses of the invention may be in the form of apowder, granules, or pellets.

Suitably, the solid non-structural dispenser is a particulate soliddispenser, for example, a powder dispenser, suitably an automated powderdispenser.

Suitably the solid non-structural dispenser is operable to dispensesolid(s), suitably particulate solids such as powders and granules, in ametered (i.e. metered-dose) manner. Such dispensers may be integratedwith the apparatus of the invention, and in some embodiments part or allof the non-structural dispenser may be incorporated within the 3Dprinter itself. Various existing technologies could be viably integratedin such a manner. For example, the DisPo™ powder dispensing technologyof BioDot™ (wWW.biodot.com) enable the metered dispensing ofsolids/powers at individual doses ranging from 100 μg to 20 mg. Such adispenser comprises a sampling cavity, to sample a metered dose (e.g. ofa core composition), and a sample ejection system to dispense thesampled solid.

The solid non-structural dispenser suitably comprises a primary storagecontainer, such as a hopper. The primary storage container suitablycomprises a solid (suitably particulate) core composition or precursorthereof. The primary storage container is suitably sealed. The primarystorage container may be in the form of a cartridge specially adaptedfor compatibility with the apparatus of the invention. The primarystorage container suitably has either an outlet (such as avalve-operated tap, optionally in conjunction with a positive dispensingmeans, such as a pressurizer or agitator) through and from which itscontents may be dispensed, or a sampling port from which contents may beextracted by an external sampling element.

The solid non-structural dispenser suitably comprises one or moredispensing vessels. Suitably such dispensing vessels are configured toreceive a quantity of core composition (or precursor thereof) from theprimary storage container, suitably either directly or via a conveyingmeans. Suitably the one or more dispensing vessels may receive apre-determined dose of core composition (or precursor thereof).

The solid non-structural dispenser suitably comprises a quantifyingcomponent, for example, a gravimetric or volumetric component. Such aquantifying component suitably weighs or otherwise quantifies each doseof solid to be dispensed. Suitably the non-structural dispenser isoperable to convey a quantity of a core composition (or precursorthereof) from the primary storage container to the quantifying componentor to a dispensing vessel that interacts with the quantifying component.Suitably, one or more dispensing vessels are located so that quantifyingcomponent(s) can quantify the amount of core composition received by thedispensing vessel(s). Alternatively, the quantifying component may beassociated with the primary storage container and thereby measure a massreduction as solid is dispensed therefrom. Quantification may beperformed by weight and/or by volume.

The solid non-structural dispenser suitably comprises a flow-controlcomponent, which suitably controls and meters the distribution of a corecomposition (or precursor thereof) from the primary storage container tothe one or more dispensing vessels. A flow-control component may, forexample, comprise a controlled feed mechanism, and may suitably comprisean Archimedes screw, a valve, an agitator (e.g. to vibrate, tap, orshake). Alternatively or additionally, the flow-control component maycomprise a sampling probe operable to sample a (estimated) quantity of asolid from the primary storage container—the sampling probe may suitablydispense solid directly into a (part-formed) solid dosage form, thoughpreferably the sampling probe will first dispense solid into adispensing vessel in order to accurately verify the quantity thereof tobe ultimately dispensed.

The solid non-structural dispenser suitably comprises an expellingmechanism for expelling quantified amounts of core composition (orprecursor thereof) from either a sampling probe or dispensing vessel.Such an expelling mechanism may suitably comprise a release means (e.g.a tap, valve, vacuum release, or other such mechanism, for example,which may tip the contents out of a dispensing vessel towards a targetdispensing point). Alternatively or additionally the expelling mechanismmay comprise an expulsion means, for example, a pressurizer, agitator,screw, piston or plunger, which forces a core composition (or precursorthereof) from the dispensing vessel(s) to thereby dispense the solid.

In one embodiment, the solid non-structural dispenser comprises a hopperand a moveable metering element (e.g. a shuttle plate) which is movablerelative to the hopper and comprises a metered cavity/container of afixed or adjustable size. The size of the metered cavity determines thesize of each dose. The moveable metering element may be operable toreceive a quantity of solid from the hopper before encapsulating ametered quantity thereof within the cavity, moving to a dispensingpoint, and dispensing the solid from the metered cavity.

The skilled person will be aware of certain challenges faced in themetered dispensing of solids, especially particulate solids. Forcesacting in favour of outflow (e.g. gravity, pressure, and/or screw forcessuch as those of an Archimedes screw) are often counterbalanced byforces acting against the flow—for example: interparticle adhesion,adhesion to parts of the dispenser (e.g. walls of dispenser and/ordispensing outlet), abrasion, friction, erratic flow (e.g. creatingrathole or arch profiles during funneling), compressibility(non-compressible solids flow better), outlet restriction (e.g. the boreof the outlet), angle of repose during funneling (angles less than orequal to 35° are preferred), external pressure (an external vacuum canassist) etc. Outflow of particles is particularly influenced by theparticles themselves, in terms of particle shape, particle size,particle density, chemical nature of particles, surface roughness, andmoisture content. Particle flow can be improved through judiciousparticle engineering, including techniques such as particle enlargement(e.g. granulation), cohesion reduction, smoothing/rounding, optimisationof moisture content, co-milling (e.g. to form flow-enhancingnanocoatings), and such like. A compressibility index less than or equalto 25%, preferably less than or equal to 15%, preferably 10%, isreassuring for better particle flow. Moreover, particle sizes greaterthan or equal to 10 μm, suitably greater than or equal to 50 μm,suitably greater than or equal to 100 μm, are often preferable foroptimal particle flow. As such, small particle sizes, includingnanoparticles (e.g. less than or equal to 100 nm), may be betterdispensed in the form of suspensions, such as nanosuspensions.

Suitably the components of the solid non-structural dispenser arecomputer-controlled, and suitably any valves or pressurizers areelectronically controlled.

In some embodiments, the solid non-structural dispenser may simplycomprises a hopper with an outlet valve which is operable (preferablyunder computer control) to dispense a metered quantity of particulatecore composition (or precursor thereof) directly from the hopper into apartial shell of the solid dosage form. Dispensation of the particulatesolid may be entirely gravitational, or may be facilitate through theapplication of additional pressure to the hopper or within the outlet.

Suitably, a clench valve may be incorporated within a solidnon-structural dispenser to control dispensation flow of particulates,such as granules.

Liquid Non-Structural Dispensers

Liquid dispensers (which suitably includes suspension, dispersion, andemulsion dispensers) are generally more straightforward then soliddispensers because they face fewer challenges.

The non-structural dispenser may be or otherwise comprise any suitableliquid dispensing apparatus. Various liquid dispensing apparatuses areknown in the art. The core composition (or precursor thereof) fordispensing by the apparatuses of the invention may be in the form of aliquid, for example, a solution, dispersion, emulsion, or suspension.

Suitably, the liquid non-structural dispenser is an automated liquiddispenser.

Suitably the liquid non-structural dispenser is operable to dispenseliquid(s) in a metered (i.e. metered-dose) manner. Such dispensers maybe integrated with the apparatus of the invention, and in someembodiments part or all of the non-structural dispenser may beincorporated within the 3D printer itself. Various existing technologiescould be viably integrated in such a manner. For example, the dispensermay comprise a syringe driver (or syringe pump), suitably an automatedsyringe driver. Suitably the liquid non-structural dispenser is operableunder computer control to dispense a metered dose of liquid into eachsolid dosage form (or each partially-formed dosage form). Suitably theapparatus of the invention is operable under computer control tocoordinate metered dispensing of each dose of core composition (orprecursor thereof) with the shell fabrication process.

Though, like solids, metered dispensing of liquids can be performed invarious ways, including both gravimetrically and volumetrically,preferably liquids are volumetrically dispensed.

Like with solid non-structural dispensers, the dispenser may comprises aprimary storage container. However, in the case of liquids the primarystorage container may be fluidly-linked directly to the ultimatedispensing outlet, as per a syringe, since precise dispensing of liquidsis viable through volumetric dispensing without requiring subsequentquantitative checks.

As with solid dispensing, the liquid non-structural dispenser maycomprise an outlet and optionally a pressurizing means. As such, liquidmay be dispensed under gravity, vacuum or such like, and/or may bedispensed under pressure, for instance, from a piston/plunger. Suitablythe components of the liquid non-structural dispenser arecomputer-controlled, and suitably any valves or pressurizers areelectronically controlled.

Build Platform

The printing apparatus or 3D printer suitably comprises a buildplatform. This provides a platform upon which the solid dosage form(s)(especially shells and partial shells) may be printed.

Suitably, during printing (e.g. at the relevant printing operatingtemperature), the surface of the build platform onto which the soliddosage form is to be printed adheres to the solid dosage form (or atleast to the layer thereof in contact with the build platform)sufficiently to prevent movement of the developing solid dosage formduring printing. Suitably, however, after printing (e.g. optionally at adifferent temperature to the printing operating temperature) the printedsolid dosage form(s) may be removed from the build platform withoutbeing damaged (e.g. the build platform is non-adherant enough to allowthe solid dosage forms to be removed or is selectively tunable, e.g. bychanging the operating temperature, to allow the solid dosage forms tobe removed therefrom). As such, the surface of the build platform maycomprise a surface coating or surface tape which imparts the requiredsurface properties (e.g. adhesive but not too adhesive that the soliddosage forms are permanently adhered).

The build platform is suitably configured or operable to maintain asurface temperature (i.e. for the surface in contact with the soliddosage form) during printing of less than or equal to 50° C., suitablyless than or equal to 40° C., suitably less than or equal to 30° C.,suitably greater than or equal to 5° C., suitably greater than or equalto 15° C. In other embodiments, the build platform is operable tomaintain a surface temperature of less than or equal to 150° C.,suitably less than or equal to 100° C., suitably greater than or equalto 15° C. This may be achieved through selective operation of heatingand/or cooling elements associated with (e.g. lying beneath) the surfaceof the build platform. In a particular embodiment, the build platform isoperable and preferably operated to maintain a surface temperature ofbetween 20 and 90° C., suitably between 20 and 60° C., suitably between30 and 50° C., most suitably about 40° C.

The build platform may be movable (suitably in an automated fashion orin a manner controlled by a computer or by the printer under instructionfrom the computer) to control the position or height of extrusion of arelevant filament upon the build platform. The build platform may bemoveable in any or all of the X, Y, and Z direction, though in someembodiments the build platform is movable in the Z direction only, i.e.up and down. Movement in the Z direction allows the gap (or height)between the nozzle and the printing point to be kept substantiallyconstant throughout the printing process to maintain layer-by-layerconsistency.

3D Printer

The 3D printer is suitably an FFF 3D printer. Conventional FFF 3Dprinters are well known in the art, and are generally suitable for usewith the present invention, though they may be judiciously modifiedbased on the principles outlined herein to optimise printing of soliddosage forms. For the skilled persons reference, the following researcharticles describe a viable operation of FFF 3D printers—S. H. Masood,“Application of fused deposition modelling in controlled drug deliverydevices”, Assembly Automation, 27/3 (2007), p. 215-221 and Khaled et al,“Desktop 3D printing of controlled release pharmaceutical bilayertablets”, International Journal of Pharmaceutics, 461 (2014), p.105-111—describe printing with FFF 3D printers of filaments, albeitthere are no active ingredients contained within the filaments beingprinted (drug compounds are infused at a later stage). Furthermore, PCTpublication WO2016/038356 by the present application, which is herebyincorporated by reference, also describes suitable equipment for usewith the present invention.

FFF 3D printers suitable for use with the invention generally comprise aheated/heatable extruder nozzle which melts and deposits (suitably ontoa build platform) molten filament in a layer-by-layer fashion. Thedeposited molten filament suitably hardens rapidly following deposition.Maintaining a build platform with a relatively low surface temperaturemay facilitate such cooling/hardening to improve the final structure ofthe solid dosage form being printed. The FFF 3D printer also suitablyincludes one or more nozzle heaters (suitably one associated with eachnozzle but optionally one serving multiple nozzles) and suitably one ormore conveyors (suitably one associated with each filament and/ornozzle) as defined above. Suitably the FFF 3D printer comprises one ormore filament spool zones (or filament spool attachment points) forholding the relevant filament spool(s).

The FFF 3D printers of the invention may be adapted to incorporate on ormore non-structural dispersers as defined herein. In such a manner,structural printing and non-structural dispensing may occur atsubstantially the same time.

Computer

The apparatus, including the 3D printer (and optionally the buildplatform), is suitably operable via the computer, suitably a computerrunning pursuant to specialist solid dosage form printing software, andoptionally also to one or more databases, to print the solid dosage formupon the build platform, suitably via a process involving the printingand/or extrusion of an shell-forming printing filament and optionally.The computer suitably also controls and coordinates the dispensing ofcore composition(s) (or precursor(s) thereof), optionally simultaneouslyor sequentially with the printing of shells.

It will be readily understood by those skilled in the art that any oneor more of the build platform, printing filaments, and/or computer,and/or any part thereof, may suitably be integrated within or form apart of the 3D printer. In an embodiment, the printing apparatus isessentially a 3D printer or printing apparatus.

The printing apparatus suitably includes or is otherwise connected to acomputer. The printing apparatus (or 3D printer) are suitably connectedto the computer via an interface (suitably a digital interface), whichmay be wired (e.g. a port-to-port connection via an appropriate datalead, e.g. a USB lead) or wireless. The computer may be located at thesite of the relevant printing apparatus or 3D printer (i.e. a localcomputer). However, the invention is equally applicable where therelevant computer (or computers) is located remote from the site of therelevant printing apparatus or 3D printer, but both the printingapparatus (or 3D printer) and remote computer comprise or are otherwiseconnected to respective communicators allowing the remote computer andprinting apparatus (or 3D printer) to communicate with one another. Inthis manner, a remote computer may be caused to operate the printingapparatus. In a particular embodiment, the printing apparatus (or 3Dprinter) may be connected to a network so that multiple remote computers(and/or local computers) may communicate therewith to cause theoperation of the printing apparatus (or 3D printer).

The computer associated or otherwise connected with the printingapparatus suitably controls printing of the relevant filament(s) inaccordance with a solid dosage form design and/or solid dosage formparameters (e.g. relative amounts and juxtaposition of ingredients) setforth in a given solid dosage form data file (e.g. in a CAD or a .STLfile), suitably as interpreted by relevant software pursuant to whichthe computer runs.

In a particular embodiment, the printing apparatus comprises or isconnected to a local computer, and both printing apparatus and the localcomputer are located on site at a pharmacy, most suitably in apurpose-build printing area or room (which may be suitably haveregulatory approval).

Suitably the method and/or apparatus involves a computer runningpursuant to solid dosage form printing software (and optionally one ormore internal and/or external databases).

Suitably, a computer running pursuant to said to solid dosage formprinting software is configured to obtain information regarding one ormore parameters (optionally including physical design parameters, suchas shape) pertaining to the solid dosage form to be printed (e.g. be itfrom information inputted manually by a user or information obtainedautomatically from another data source). Suitably the computer pursuantto said to solid dosage form printing software is configured to requestmanual user input via a user interface (e.g. keyboard/screen) regardingone or more parameters pertaining to the solid dosage form to beprinted. For example, a user (which may be a pharmacist acting underinstruction from a patient and/or doctor) may be requested to inputinformation regarding patient name, patient reference number (e.g.healthcare number), and/or another reference name or number, followingwhich the computer may communicate (via relevant communicatorsassociated therewith) with one or more databases (be it local or remote,wired or wirelessly, e.g. via a network such as the internet) toautomatically call further information and/or options corresponding withsaid name or reference (e.g. personal patient data, medication history,repeat prescriptions, data or partial data relating to solid dosageforms to be printed, including solid dosage form data files containingdesigns and/or other relevant parameters). Thereafter, the user may berequested to manually input or manually select further information (e.g.drug, drug dose, release profile, etc.) and/or options to allow thecomputer to obtain all relevant information pertaining to the printingof the desired solid dosage form. Alternatively or additionally, theuser may be requested to manually input or call information relating toone or more specific parameters pertaining to the solid dosage form(e.g. drug name/reference, drug dose, drug release requirements, colour,size, shape, solubility, packaging labelling information, etc.).Suitably, any user input may be logged and/or stored for futurereference or for repeat prescriptions, etc.

There are a variety of ways the computer may be configured to obtain therelevant information to allow a solid dosage form to be printed, but itis likely that a variety of pre-set information may be used (e.g.certain approved formulations/filament combinations for producing a givesolid dosage form). As such, the computer may suitably be associatedwith or connected/connectable with a solid dosage form database(suitably a central database accessible via a network, such as theinternet) which provides all necessary pre-set information (e.g. datafiles relating to the solid dosage form and details of variableparameters such as drug dose levels/limits).

Suitably, a solid dosage form design for printing (and optionallyparameters connected therewith) may be recorded in a solid dosage formdata file, which may be read by a computer running pursuant to the soliddosage form printing software.

Suitably, a computer running pursuant to said to solid dosage formprinting software is configured to calculate the mass and/or volume ofthe solid dosage form to be printed based on the information obtained.Suitably once the computer has obtained all required information (be itinformation manually inputted by a user, information importedautomatically, or a combination of both) it is configured to performcalculations to allow finalisation of printing instructions before thecomputer controls printing. At this stage, further input may be requiredor requested (e.g. via a user interface), for instance dimension(s)and/or shape modifications may be optionally selected. Calculationstypically relate to the mass and/or volume of a given solid dosage formrequired to provide a given active dosage per dosage form. Though it maybe possible to increase the concentration of a given active relative toother ingredients (e.g. excipients), typically formulations areoptimised and relative proportions fixed/pre-set, whereas overallmass/volume may be varied whilst retaining the same relative proportionsof ingredients.

Suitably, a computer running pursuant to said to solid dosage formprinting software is configured to control printing of and relativeproportions of ingredients within the solid dosage form, suitably basedon the information obtained and suitably based on the calculationsperformed. Suitably “controlling printing” includes initiating printinga terminating printing and any or all printing operations therebetween.

Suitably during printing, operational data is collected (optionally byone or more local and/or remote computers and/or databases) and suitablystored (most suitably at a central computer which may analyse such data,e.g. for quality control monitoring, monitoring of malfunctions,monitoring of batches, monitoring of dosage forms dispensed to a givenpatient, etc.). Suitably the printing apparatus comprises or isotherwise associated with one or more operational sensors (e.g. nozzletemperature sensors, filament feed rate sensors or conveyor sensors,overall temperature sensors, build platform sensors which may, forexample, monitor surface temperature and/or rate of post-print cooling,etc.) which feedback operational parameters/information to a computer,database, or data storage facility, relating to the the operation of theprinting apparatus and elements associated therewith during the printingof each dosage form. Most preferably, such operational data iscollected, stored, and/or otherwise transmitted to a central computer ordatabase to enable independent auditing of any given printing apparatus.This may be important in order to maintain quality control, and maintainappropriate records in order to retain regulatory approval of any given3D printing system.

Suitably, a computer running pursuant to said to solid dosage formprinting software is configured to control performance of one or morefurther processing steps.

Software and Data Files

The computer operating the printing apparatus or 3D printer suitablyruns pursuant to solid dosage form printing software (and optionallyalso to one or more databases). As explained herein, this software mayconfigure the computer to obtain information and perform calculationsbefore it then configures the computer to control printing via aninterface with the printing apparatus or 3D printer.

Once the computer has obtained the relevant information and performedthe relevant calculation, suitably the software configures the computerto control printing of a solid dosage form, suitably based on a design(shape and dimensions, texture, layer structure, internal structure,porosity, colour(s), etc.) and/or parameters (relative amounts ofingredients, such as drug dose) relating to said solid dosage formcontained within one or more solid dosage form data files. The soliddosage form data files may include a design file (e.g. containing dataand/or images relating to the physical design of the solid dosage form,including its dimensions, shape, layered structure, core-shellstructure, etc.) and/or a parameter file (e.g. containing data relatingto the chemical composition of the solid dosage form, including drugtype, excipient type(s), drug dose level, excipients to control drugrelease, etc.). A single solid dosage form data file may contain alldata pertaining to the physical design and chemical composition.However, the physical design and chemical composition may be modifiedpursuant to information obtained following user input.

In some embodiments, the design file may be a CAD file depicting a soliddosage form. However, such file formats are likely to require conversionto a file format compatible with the printing apparatus or 3D printer.Conventional 3D printers generally read design files in a .STL format.As such, the design file is suitably a .STL design file depicting thesolid dosage form (or at least the physical design thereof).

The design file may include or be linked with a parameter filecontaining chemical composition details, or the two may be independent.Alternatively there may be no parameter file as such and instead therelevant parameter information may be called from a database, forinstance, in response to user input (e.g. patient reference, or drugreference, etc.).

The software may additionally configure the computer to collect, store,and/or transmit (e.g. to a central database) operational data fed backto the computer from the printing apparatus or 3D printer duringprinting. The software may configure the computer to detect and/orrespond to any (or a preset level of) deviation in expected operationaldata (e.g. if nozzle temperatures exceed a maximum preset temperaturelevel), for instance alerting the user/operator or any other interestedparty that a malfunction has occurred and that the solid dosage formsproduced during malfunctional printing should be disposed or otherwisetested.

Databases

The apparatus and/or computer(s) associated therewith may be configured(e.g. by the solid dosage form printing software) to communicate with(suitably via relevant communicator(s), and suitably via a network suchas the internet) one or more solid dosage form databases and/or patientdatabases to obtain information regarding one or more parameterspertaining to the solid dosage form to be printed. For example, suchdatabase(s) may be consulted in response to a user input (e.g. patientreference number) to furnish the computer with the relevant information(or relevant information to be supplemented by further user input) toenable calculations and printing to be performed.

By way of example, a patient database comprising patient records formultiple patients (which records may include, for example, patient name,patient reference number, medical data, medical history, etc.) suitablycontains information (which may merely be a cross-reference or referencenumber relating to information residing in another database, such as asolid dosage form database) regarding the solid dosage forms to beprinted for each patient. Where the “information” is a cross-referenceto a solid dosage form database, this solid dosage form database maythen be consulted for further information regarding the solid dosageform. This information may be any of the information defined herein,though optionally the printing apparatus or computer(s) associatetherewith may be instructed (e.g. via a user interface) to modify theinformation (e.g. drug dose level) prior to calculations and/orprinting. Any of these database may be accessible to interested parties,preferably securely accessible (to maintain confidentiality of certaindata), to enable the relevant information (be it in a patient database,solid dosage form database, or both) to be retrieved and/or amended asrequired (e.g. if a patient needs an increased dose in the printed soliddosage forms or a different active release profile). Suitably suchdatabase(s) may be wirelessly accessible via a network, such as theinternet. Such database architectures are well known in the art.

The or each printing apparatus and/or computer(s) associated therewithmay be configured (e.g. by the solid dosage form printing software) tocommunicate with (suitably via relevant communicator(s), and suitablyvia a network such as the internet) one or more apparatus-monitoringdatabases configured to transmit to and store within said database (andoptionally analyse and/or report upon) operational data collected(optionally by one or more local and/or remote computers and/ordatabases) during each printing operation (i.e. each time a printingapparatus prints). As described herein, such operational data issuitably obtained/delivered by sensors associated with each givenprinting apparatus, suitably sensors associated with key parts of theapparatus that could affect the quality of the ultimate solid dosageforms. The operational data may be transmitted to said database in realtime, following printing, or at any suitable time (e.g. at night toavoid unnecessary overloading communication networks during work hours).Such apparatus-monitoring databases may be organised with a record foreach printing apparatus, and may suitably maintain a log of operationaldata each time said printing apparatus is operated. Suitably each set ofoperational data is cross-reference to a given patient a solid dosageform, suitably so that if any operational data is deemed malfunctional,the relevant interested parties can be alerted. In this manner, eachprinting apparatus may be monitored (whether in real time or otherwise,whether automatically or otherwise) and data periodically submitted tosatisfy regulatory requirements. Moreover, central apparatus-monitoringdatabases may trigger a response to any perceived malfunction of a givenprinting apparatus. Moreover, a response may be triggered which preventsthe relevant malfunctional printing apparatus from being used until itsperformance can be revalidated.

Again, any of the one or more apparatus-monitoring databases may beaccessible to interested parties, preferably securely accessible (tomaintain confidentiality of certain data), to enable the relevantinformation to be retrieved and/or analysed as required (e.g. ifregulatory bodies wish to check that a given printing apparatus has beenin good order throughout a given period, or if machine maintenanceprofessionals which to use the data to diagnose a problem in order torestore the performance of a given printing apparatus). Suitably suchdatabase(s) may be wirelessly accessible via a network, such as theinternet. Such database architectures are well known in the art.

Method of Printing Solid Dosage Form and/or Using the Apparatus

The present invention also provides a method of preparing (or printing)a solid dosage form, suitably as defined herein. Suitably this method isa method of using the aforesaid apparatus. As such, the method maysuitably comprise providing a solid dosage form printing apparatus asdefined herein.

The method suitably comprises operating the apparatus to produce acore-shell-based solid dosage form, suitably upon the build platform,through the 3D printing of a shell and the dispensing of a corethereinto. Suitably, such production is performed via acomputer-implemented process (i.e. where printing and dispensing arecontrolled and suitably initiated by a computer that is connected orconnectable to or within the apparatus, be it in a wired or wirelessfashion).

The method suitably involves printing a three-dimensional partial shellonto a build platform. partial shell is suitably an open shell. The openshell suitably comprises a shell composition, suitably formed by theprinting of a shell composition (or precursor thereof). Such printingsuitably involves 3D printing, preferably FFF 3D-printing. As such, the3D-printing may comprise printing with one or more printing filaments,wherein at least one printing filament comprises or consists of theshell composition (or precursor thereof). The shell composition (orprecursor thereof) is suitably printed via the structural printingnozzle of the apparatus of the invention.

The method suitably involves dispensing a core composition (or precursorthereof) into the partial or open shell. Such dispensing suitablyresults in an open core-containing shell. The core composition (orprecursor thereof) is suitably dispensed via the non-structuraldispenser of the apparatus of the invention.

The method suitably involves closing the shell, which suitably affords acomplete shell around a core. Suitably the shell is closed after thecore composition (or precursor thereof) is introduced into the (partial)shell. Suitably the method involves closing the open core-containingshell, suitably by printing a closure thereupon (i.e. to cover orotherwise seal the opening of the open core-containing shell). Suitablythe closure comprises a shell composition, suitably the same shellcomposition as the partial shell. Suitably a shell composition (orprecursor thereof) is printed to form the closure. Suitably the shellcomposition (or precursor thereof) is printed via a structural printingnozzle, which may be the same or different to the structural printingnozzle employed to print the partial shell.

The method may include one or more further steps before, during, and/orafter any of the aforesaid steps. For example, for example, the shellformed from the shell composition of the invention may be an inner or anouter shell of a multi-shell solid dosage form. As such, second andsubsequent shells may be formed simultaneously with the shell of theinvention. Such additional shells may be useful for tailoring therelease profile of the active within the core, or may serve anotherpurpose, such as providing an inert barrier between the principle shelland the core to mitigate any reactions therebetween. Alternatively, theinternal or external surface(s) of the principle shell may be pre- orpost-treated, whether through the printing of an additional layer orpartial layer, or through alternative coating techniques well known inthe art.

In certain embodiments the method may involve the dispensing of one ormore further core composition precursors or reactants into the openshell, either before or after the principle core composition (orprecursor thereof) has been dispensed thereinto. The addition of furthercore precursors or reactants allows reactions and transformations totake place in situ within the core. For example, a pH adjust (e.g. acidor alkali/base) may be dispensed into the open shell before or after theprinciple core composition (or precursor) to induce a pH change thatresults in a chemical or physical transformation, such as in situgelling.

In alternative embodiments, the dispensing of additional coreprecursor(s) and/or reactant(s) may take place simultaneously with thedispensation of the principle core composition (or precursor), forinstance multiple precursors may become mixed during printing,potentially even before reaching the interior of the open shell.

A solid dosage form produced via methods of the invention may besubsequently treated in a variety of ways to afford a further-processedsolid dosage form. For instance, a solid dosage form may be entericallycoated by standard enteric coating treatments known in the art.Likewise, other release-controlling properties may be imparted to asolid dosage form by further processing which, for example, provides thesolid dosage form with one or more shells.

Though multi-phase printing—involving production of a partial shell,partial shell filling with a core composition, and subsequent completion(or closure) of the shell—tends to result in fewer troubleshootingissues and a higher success rate, in alternative embodimentssingle-phase printing may be employed, which may suitably involveinterchanging printing of the shell with dispensing of the corecomposition. Such single-phase printing may allow for greater volumes ofcore composition within the shell.

Most suitably, all steps (including any further processing steps) areperformed by the printing apparatus, and are suitably controlled by thesame computer.

Printing an Open Shell

The printing of a three-dimensional open shell onto a build platform issuitably performed via FFF 3D-printing, suitably with one or morefilaments that collectively comprise a shell composition (orprecursor(s) thereof). Most suitably, a single filament comprises orconsists of the shell composition (or precursor thereof). Suchfilament(s) are suitably printed via a structural printing nozzle asherein described.

Initially, a printing filament comprising a shell composition (orprecursor thereof) suitably resides within the apparatus (or printer) ina storage position, suitably on a filament spool, suitably within acartridge. The printing filament is suitably conveyed via one or moreconveyors (e.g. rollers) to the structural printing nozzle. Printingfilament is then extruded through the structural printing nozzle(suitably whilst filament continues to be conveyed towards the nozzlefrom a storage position). Printing through the structural printingnozzle suitably involves melting and/or softening the filament to allowit to be deposited onto the build platform, suitably in a layer-by-layerfashion. Suitably the relevant printing filament composition solidifiesafter being deposited onto the build platform or onto a layer that hasalready been printed upon the build platform. Suitably a 3D shape (inthis case an open shell) is constructed in a layer-by-layer fashionthrough judicious depositing according to a pre-defined blueprint.

The structural printing nozzle is suitably heated at an operatingtemperature as herein described to facilitate melting and/or softeningof a printing filament. The nozzle suitably prints filaments at one ormore of the operating speeds herein described.

The structural printing nozzle is suitably moved during the printing ofmultiple open shells, suitably in any or all of the X, Y, Z direction.

Once printed, the open shell suitably rests on the build platform,suitably resembling a small cup. Suitably the open shell comprises anopening, suitably an opening accessible to a dispenser of a corecomposition (or precursor thereof). Suitably, the build platformunderlies the open shell and the shell opening is at the top of theshell. As such the open shell is suitably a container. The shellsuitably comprises a concave interior which may be rounded. The shellmay be considered to comprise wall(s), though in practice the shell maybe a single rounded continuum.

Suitably, a plurality of open shells are printed upon the build platformbefore any core compositions are dispensed from a non-structuraldispenser.

It will be understood by those skilled in the art that the, each, or anynozzle may be adapted to suit the properties a corresponding filamentconfigured to print thereto. The nozzle properties/design and filamentproperties/composition suitably complement one another so as tofacilitate controlled extrusion of said filament (be it continuous orintermittent, e.g. where more than one filament is used in the printingof a solid dosage form), suitably without any nozzle blockages orimpedance, and suitably without any unacceptable degradation ofingredients within the filament during the printing process.

Dispensing the Core into the Open Shell

Following the printing of one or more (open) shells onto the buildplatform (suitably after a plurality of open shells has been printedthereupon), a core is suitably dispensed into the one or more shells.Suitably the core is dispensed into the or each shell by dispensing acore composition (or a precursor thereof) into the open shell, whichsuitably results in a core-containing open shell. The core composition(or precursor thereof) is suitably dispensed from the non-structuraldispenser of the apparatus of the invention.

Suitably, the method comprises dispensing a core composition (orprecursor thereof), which is a fluid composition (i.e. is suitablycapable of flowing under gravity) such as a particulate solid or aliquid (including solutions, suspensions, etc.), into the or each openshell, suitably a pre-determined quantity thereof.

Suitably the core composition (or precursor) is at or below atemperature of 90° C., suitably at or below 75° C., suitably at or below60° C., suitably at or below 50° C., suitably at or below 40° C., moresuitably at or below 30° C., suitably at or above 0° C., suitably at orabove 10° C., during its dispensation through the non-structuraldispenser.

Where the ultimate core composition (formed within the solid dosageform) is different to a core composition precursor, the method maysuitably involve the dispensing of one or more core compositionprecursor and/or reactants. For example, a first core compositionprecursor and/or reactant may be first dispensed into an open shell(wherein it is contained) before a second core composition precursorand/or reactant is dispensed thereinto. In such embodiments, a chemicalreaction between the core composition precursor(s) and/or reactant(s)may change the overall composition. Such a chemical reaction may evenchange the physical form of the composition—the resulting corecomposition may be a solid, liquid, or even a gel. In an embodiment, oneof the core composition precursor(s) may be an active-containing coreprecursor, whilst another of the core composition precursor(s) may be apH adjuster (e.g. comprising an acid, base, and/or buffer) which changesthe pH of the active-containing core precursor to cause either or both achemical and/or physical change. In a particular embodiment, theactive-containing core precursor may be dispensed as a liquid but may betransformed to a solid or gelled core composition.

In some embodiments, the aforementioned mixing of core compositionprecursor(s) and/or reactant(s) may occur during dispensation (or evenbefore if a chemical reaction is slow enough not to compromisedispensing) in a mixing chamber. For example, the dispensing of the corecomposition may involve dispensing two or more core compositionprecursor(s) and/or reactant(s) into a mixing chamber before beingultimately being dispensed into the open shell(s). In this manner, morehomogeneity may be achieved in the overall core composition. The mixingchamber may need to be sufficiently small to avoid accumulation ofblocking materials.

In preferred embodiments, the core composition in the final solid dosageform is the same as the core composition dispensed from the apparatus ofthe invention and no modifications of the composition ensue. As such,the core suitably comprises the core composition as per that dispensedfrom the non-structural dispenser.

The method suitably comprises dispensing individual doses of a corecomposition (within each open shell) which comprise between 0.1 μg and1000 mg of active ingredient per individual dose, suitably between 1 μgand 500 mg, suitably between 10 μg 50 mg, suitably between 100 μg and 10mg.

Where the core composition (or precursor thereof) to be dispensed is aparticulate solid, dispensing thereof suitably comprises sampling ofsaid solid from a primary storage container (which may be performed byextracting particulate solid from said storage container with a samplingprobe or such like, or by receiving particulate solid expelled from saidstorage container into a vessel), suitably in a quantitative manner.Suitably the sampled particulate solid is quantified (suitably inaddition to any preliminary quantification during sampling), suitablygravimetrically. Individual dose(s) of quantified particulate solid arethen suitably dispensed into an open shell(s), suitably in a forcedmanner (e.g. using pressure to push the solid, or reduced pressure topull the solid).

In contrast to the printing of the shell, which is characterised by amultiplicity of printed layers, the core is suitably dispensed en masseor as a bulk (i.e. as a single volume or mass directed to the sametarget location). Suitably upon printing the core composition (orprecursor thereof) collapses and spreads to the dimensions of the openshell due to its relative fluidity. The open shell acts as a containerto facilitate the methods of the invention.

Where the core composition (or precursor thereof) to be dispensed is aliquid, suitably said liquid is dispensed in a volumetric manner,suitably via a syringe or syringe driver.

Closing the Shell to Encapsulate the Core

Suitably a “filled” open shell (core-containing open shell) is closed byprinting a printing composition (e.g. using a filament, where FFF3D-printing is employed) through a structural printing nozzle as definedherein onto the “filled” open shell. The printing composition employedfor closing the shell may be the same or different to the shellcomposition (or precursor) used for printing the open shell, though mostpreferably it is the same and is printed via the same printing nozzle(or similar or identical printing nozzle at another station within theoverall apparatus). Most suitably, the open shell is closed using thesame printing methods described above in relation to the printing of theopen shell.

Computer-Implementation of Method

The method of preparing a solid dosage form is suitably acomputer-implemented method, suitably as defined herein.

The method suitably involves providing a solid dosage form printingapparatus, suitably as defined herein, and operating said apparatus toprint the solid dosage form. Suitably the apparatus includes or isotherwise connected to a computer. Operating the apparatus suitablyinvolves operating a computer, which is suitably connected (be it in awired or wireless fashion) with or within the relevant printingapparatus (so as to allow the computer to control and coordinate otherparts of the apparatus, suitably including an FFF 3D printer), to causeprinting of a solid dosage form.

A computer that is comprised of or otherwise associated with anapparatus of the invention may be suitably referred to as a printingcontrol computer (or printing computer). The printing control computermay serve a different function (and may be a distinct entity) to other“computers” referred to herein, such as monitoring computers andanalytical computers, though a single computer may perform thefunction(s) of one or more of any combination of these computers. Aprinting control computer suitably controls both the printing of a shellcomposition (or precursor) through a structural printing nozzle and thedispensing of a core composition (or precursor) through a non-structuraldispenser. Wherever a different computer is used to implement each ofthese operations, said computers are suitably coordinated and may thusbe considered to be a part of one overall computer.

Printing of solid dosage forms is suitably controlled by a computer,running pursuant to solid dosage form printing software, suitably basedon information provided to the computer by user input(s) (drug type,drug dose level), databases (e.g. patient database and/or solid dosageform databases), and/or data files (e.g. design and/or parameter files),as described herein. Suitably an FFF 3D printer is configured to printpursuant to instructions provided by the computer by: feedingfilament(s) to and through their respective nozzle(s) at the appropriateintervals and/or at the appropriate rates; heating the relevantnozzle(s) at the appropriate temperature(s) for the appropriate time;and by moving the nozzle(s) and/or build platform to enable systematiclayer-by-layer printing in accordance with the relevant informationobtained and calculations made by the computer. Such printing issuitably also coordinated with the dispensing of a core composition (orprecursors), which is likewise controlled based on information providedto the computer by use input(s), databases, etc. This includescoordinating the quantities being dispensed, in line with the volume ofthe relevant printed shells, as well as timing of such dispensing—whichcan only occur after the structural foundations (e.g. open shells) havebeen printed.

The feeding of filament(s) to and through their respective nozzle(s) issuitably facilitated by a conveyor (or roller) as described elsewhereherein. Such a conveyor is suitably situated along a filament flow pathof a given filament, suitably between a filament source (e.g. a filamentspool or cartridge) and an extrusion nozzle to and through which thegiven filament is assigned to flow.

The extrusion nozzle(s) (including structural printing nozzle(s)) aresuitably controlled by the computer according to the “obtainedinformation” regarding the solid dosage form (e.g. design and/or otherparameters). Nozzles are suitably controlled to extrude a given filamentupon a build platform (or upon a partially build solid dosage form uponthe build platform) to a pattern pre-defined by the “obtainedinformation”. As such, the or each nozzle may be controlled to switch“on” and “off” in accordance with a pre-defined schedule to deliver therequired pattern in the construction of the solid dosage form. A nozzlemay be switched “on” by causing an output opening to open, by adjustingthe nozzle's operating temperature (e.g. increasing it so as to causemelting of the relevant filament), by operating the a conveyor to feedfilament through the nozzle, or a combination of any or all of theaforementioned. Naturally, a nozzle may be switched off by causing anoutput opening to close, by adjusting the nozzle's operating temperature(e.g. decreasing it to a temperature which does not cause melting of therelevant filament), by operating the a conveyor to restrict or ceasefeeding of a filament through the nozzle, or a combination of any or allof the aforementioned. The temperature of the nozzle(s) are suitably setand controlled by the computer according to the properties of thefilament in question, as described elsewhere herein. Suitably, theoperating temperature of an extrusion nozzle through which a printingfilament passes is between 90 and 220° C., more suitably between 120 and190° C., suitably between 165 and 190° C., suitably between 140 and 170°C. Suitably, the operating temperature of an extrusion nozzle throughwhich a printing filament is between 80 and 300° C., more suitablybetween 100 and 220° C., suitably between 120 and 190° C. However, theoperating temperature of an extrusion nozzle may be as low as 65° C.,especially in systems that employ low-melting polymers (e.g. PEG) orpolymers with low glass transition temperatures. Most suitably, theextrusion nozzle temperature is set to at least 70° C. In a particularembodiment, the nozzle temperature is 110-160° C., suitably 110-130° C.,suitably 130-150° C., suitably 135-145° C. Suitably the operatingtemperature of an extrusion nozzle assigned to a given filament ishigher than any corresponding hotmelt extrusion temperatures used in theformation (i.e. via extrusion) of the given filament, suitably between30 and 90° C. higher, more suitably between 50 and 70° C. higher.

The non-structural dispenser(s) are suitably controlled by the computeraccording to the “obtained information” regarding the solid dosage form(e.g. design and/or other parameters). As such, the or eachnon-structural dispenser may be controlled to switch “on” and “off” inaccordance with a pre-defined schedule to deliver the required amountsto the relevant open shells of the solid dosage form during theirconstruction. A non-structural dispenser may be switched “on” byactivated dispensing mechanisms, which may suitably involve samplingand/or dispensing depending on whether solids or liquids are beingdispensed. Naturally, a non-structural dispenser may be switched “off”by deactivated the aforesaid mechanism(s). The temperature of the corecomposition (or precursors) are suitably set and controlled by thecomputer according to the properties of the core composition (orprecursor) in question, as described elsewhere herein. Suitably, theoperating temperature of a non-structural dispenser is as hereinbeforedescribed. Most suitably there is no significant heating of thenon-structural dispenser or any of its components, since lowertemperatures are preferable to discourage and degradation of activeingredient(s) residing within the core composition (or precursorsthereof).

The build platform is suitably controlled by the computer according tothe “obtained information” regarding the solid dosage form (e.g. designand/or other parameters), suitably as described elsewhere herein. Thismay include controlling the operating temperature of the build platform,in particular the operating temperature of the surface of the buildplatform. Suitably, during printing, the operating temperature of thebuild platform or surface thereof is maintained substantially constant,suitably at a constant temperature +/−5° C. Such temperature control mayfacilitate cooling and/or hardening of post-deposited molten filament(s)to thereby secure the structural integrity of the solid dosage form asit is being printed. Such temperature control may facilitate adhesion ofthe developing solid dosage form to the surface of the build platformduring printing. Such temperature control may facilitate release (i.e.unsticking) of a solid dosage form after printing (e.g. the surface ofthe build platform may be heated or cooled, as appropriate, to reduceadhesion of the solid dosage form(s) thereto). During printing, thebuild platform is suitably configured or operable to maintain a surfacetemperature (i.e. for the surface in contact with the solid dosage form)of less than or equal to 50° C., suitably less than or equal to 40° C.,suitably less than or equal to 30° C., suitably greater than or equal to5° C., suitably greater than or equal to 15° C.

Solid Dosage Form

The present invention provides a solid dosage form. The solid dosageform may be a solid dosage form obtainable by, obtained by, or directlyobtained by the method for preparing a solid dosage form as definedherein.

In a particular embodiment, the solid dosage form is a pharmaceuticaldosage form.

The solid dosage form suitably comprises a core. The core suitablycomprises a core composition. The core composition suitably comprises anactive ingredient, suitably a pharmaceutically, nutraceutically, orfood-supplement active ingredient. Most suitably the active ingredientis a pharmaceutically active ingredient. The core is suitably dispensed,preferably at relatively low temperatures (as described herein inrelation to operating temperatures of non-structural dispensers), and istherefore suitably non-printed (e.g. not printed via a 3D-printingnozzle). The core composition (suitably a solid, liquid, or gel) issuitably contained within a shell.

The solid dosage form suitably comprises a shell, suitably athree-dimensional shell. The shell suitably surrounds the core. Theshell suitably comprises a shell composition. The shell is suitablyprinted (e.g. printed via a 3D-printing nozzle), suitably at relativelyhigh temperatures (as described herein in relation to operatingtemperatures of structural printing nozzles). The shell compositionsuitably comprises (or is formed from) a 3D printing composition (e.g. afused filament fabrication composition), wherein the shell compositionis suitably (structurally) solid.

In a particular embodiment, the solid dosage form is a capsule. Suitablythe capsule's shape is defined by the shell. Suitably the capsulecontains a core composition as defined herein.

Suitably the core and shell are mutually compatible, and are suitablyphysically and chemically inert to each other. For example, suitably aliquid (or indeed solid) core does not substantially dissolve ordisintegrate the shell or any component(s) thereof (especially notwithin 14 days, suitably not within 30 days, suitably not within 12months), and vice versa. Furthermore, suitably the core does not undergoa chemical reaction with the shell (especially not within 14 days,suitably not within 30 days, suitably not within 12 months). As such,suitably each of the core and shell are substantially stable in thesolid dosage form. Suitably the solid dosage form remainspharmaceutically acceptable and/or viable for at least 14 days after itsmanufacture, suitably for at least 30 days, suitably for at least 12months.

Suitably the core is physically detached from the shell. Suitably, thecore (or part thereof) is physically movable relative to the shell, orat least would be moveable in the presence of free internal space. Forinstance, in the case of a liquid, the liquid is suitably free to movewithin the shell upon agitation of the solid dosage form; and in thecase of a particulate solid, the particles are suitably free to movewithin the shell upon agitation of the solid dosage form. In some cases,audible sloshing (for liquid cores) or rattling (for solid cores) may beheard upon agitating the solid dosage form.

The core is suitably discernible from the shell (e.g. if a cross-sectionof the solid dosage form is taken) on the basis that the shell has alayered structure (by virtue of the 3D printing mechanism which printslayer-by-layer) and the core has a non-layered structure (by virtue ofthe core having been dispensed en masse into the shell).

The solid dosage form(s) of the invention are suitably for oraladministration. Most suitably the solid dosage form is a capsule, mostsuitably a pharmaceutical capsule.

The solid dosage form(s) of the invention may be immediate releasedosage forms, delayed release dosage forms (e.g. with enteric coatingsor shells), or sustained release dosage forms. The release profile ofthe solid dosage form may depend on the shell, the core, or anyadditional shells (e.g. surrounding the primary shell characterised bythe shell composition as defined herein). If the core comprisesmicrocapsules or coated granules, such coatings may influence therelease profiles. Most suitably, however, the shell is tailored toinfluence the active-release profile.

The longest dimension (D_(max)) of the solid dosage form (e.g. whetherin the X, Y, or Z direction) is suitably greater than or equal to 3 mm,suitably greater than or equal to 5 mm, suitably greater than or equalto 8 mm, suitably greater than or equal to 10 mm, suitably greater thanor equal to 12 mm. The longest dimension of the solid dosage form issuitably less than or equal to 30 mm, suitably less than or equal to 25mm, suitably less than or equal to 20 mm, suitably less than or equal to15 mm.

The shortest dimension (d_(min)) of the solid dosage form (i.e. notnecessarily the thinnest part but the maximum length of the thinnestdimension, or the shortest of the X, Y, or Z) is suitably greater thanor equal to 1 mm, suitably greater than or equal to 3 mm, suitablygreater than or equal to 5 mm, suitably greater than or equal to 8 mm,suitably greater than or equal to 10 mm, suitably greater than or equalto 12 mm. The shortest dimension of the solid dosage form is suitablyless than or equal to 30 mm, suitably less than or equal to 25 mm,suitably less than or equal to 20 mm, suitably less than or equal to 15mm, suitably less than or equal to 10 mm, suitably less than or equal to8 mm.

The volume of the solid dosage form (V_(sdf), suitably in terms of spacebounded by the shell, suitably up to and including the outer shellsurface) is suitably greater than or equal to 3 mm³, suitably greaterthan or equal to 5 mm³, suitably greater than or equal to 10 mm³,suitably greater than or equal to 50 mm³, suitably greater than or equalto 100 mm³, suitably greater than or equal to 200 mm³. The volume of thesolid dosage form is suitably less than or equal to 500 mm³, suitablyless than or equal to 300 mm³, suitably less than or equal to 250 mm³,suitably less than or equal to 150 mm³, suitably less than or equal to50 mm³.

The solid dosage forms of the invention are advantageously customisablein terms of the type/nature of active ingredient dose, the dose of theactive ingredient within the solid dosage form (be it an absolute doseper solid dosage form or the concentration of the active within thedosage form), the mass/volume of the solid dosage form (which istypically adaptable to vary the absolute dose of the active withoutchanging the concentration of the active within the dosage form), theactive release profile (which may be varied through judicious use and/ordistribution of appropriate excipients, e.g. core-shell arrangements fordelayed or sustained release), or shape and appearance (includingnovelty shapes, colours, and patterns, such as those that may helpencourage medication compliance for particular patients).

Many of the features preferred of the solid dosage form are describedelsewhere herein. For instance, features described in relation to themethod of producing the solid dosage form may suitably reflect a featureof the solid dosage form itself (e.g. layer height). Suitably the soliddosage form comprises ingredients provided by the filament(s) used inits formation (e.g. in the shell), and may be considered to compriserelevant filament compositions.

The shell of the solid dosage form has an average thickness suitablygreater than or equal to 1 μm, suitably greater than or equal to 10 μm,suitably greater than or equal to 100 μm, suitably greater than or equalto 500 μm, suitably greater than or equal to 1 mm. The shell of thesolid dosage form has an average thickness suitably less than or equalto 5 mm, suitably less than or equal to 2 mm, suitably less than orequal to 1 mm, suitably less than or equal to 600 μm.

Suitably, solid dosage forms of the invention comprise greater than orequal to 0.5 wt % active ingredient, suitably greater than or equal to 1wt % active ingredient, suitably greater than or equal to 5 wt % activeingredient, suitably greater than or equal to 9 wt % active ingredient,suitably greater than or equal to 19 wt %, suitably greater than orequal to 39 wt %. Suitably, solid dosage forms of the invention compriseless than or equal to 60 wt % active ingredient, suitably less than orequal to 50 wt % active ingredient, suitably less than or equal to 30 wt% active ingredient. Suitably, after the active ingredient, the weightbalance of solid dosage form consists essentially of carrier(s),diluent(s), and/or excipient(s) (all of which may be deemed toconstitute “excipients”).

Suitably the core constitutes greater than or equal to 1 wt % of thesolid dosage form as a whole, suitably greater than or equal to 3 wt %,suitably greater than or equal to 5 wt %, suitably greater than or equalto 10 wt %, suitably greater than or equal to 20 wt %, suitably greaterthan or equal to 50 wt %, suitably greater than or equal to 60 wt %.Suitably the core constitutes less than or equal to 70 wt % of the soliddosage form as a whole, suitably less than or equal to 55 wt %, suitablyless than or equal to 25 wt %, suitably less than or equal to 15 wt %,suitably less than or equal to 5 wt %. The shell may suitably compriseless weight than the core within the solid dosage form.

Suitably the core of the or each solid dosage form has a weight ofgreater than or equal to 1 mg, suitably greater than or equal to 5 mg,suitably greater than or equal to 10 mg, suitably greater than or equalto 50 mg, suitably greater than or equal to 80 mg. Suitably the core ofthe or each solid dosage form has a weight of less than or equal to 1000mg, suitably less than or equal to 500 mg, suitably less than or equalto 250 mg, suitably less than or equal to 100 mg.

Suitably the volume of the core (V_(core)) constitutes greater than orequal to 0.1% of the overall volume of the solid dosage form (V_(sdf)),suitably greater than or equal to 1%, suitably greater than or equal to2%, suitably greater than or equal to 4%. Suitably the volume of thecore (V_(core)) constitutes less than or equal to 50% of the overallvolume of the solid dosage form (V_(sdf)), suitably less than or equalto 20%, suitably less than or equal to 10%, suitably less than or equalto 6%.

Suitably the volume of empty space (V_(empty)—i.e. excluding the shelland core) constitutes greater than or equal to 0.1% of the overallvolume of the solid dosage form (V_(sdf)), suitably greater than orequal to 1%, suitably greater than or equal to 10%, suitably greaterthan or equal to 20%, suitably greater than or equal to 50%.

Shell, Shell Composition, Shell Filament and Shell Filament Composition

The shell suitably is or comprises a shell composition (i.e. shaped as ashell). The shell is suitably solid. The composition of the shell issuitably (substantially) the same as that of the material printed fromthe structural printing nozzle. The shell is suitably formed from ashell printing filament (e.g. an FDM or FFF filament), and thus theshell suitably is or comprises a shell filament composition, suitably anFFF filament composition. Suitably, the composition of the shell is(substantially) the same as the composition of the shell filament. Assuch, any definitions herein relating to the composition of the shellfilament (e.g. shell filament composition) may be equally applicable tothe composition of the shell per se (e.g. shell composition), even forembodiments where the shell is printed by a technique other than afilament printing technique. However, the shell composition may beconsidered a printed shell filament composition as defined herein, sincein some cases (e.g. where a degree of chemical change occurs within theshell composition during printing) the process of printing can betterdescribe the product.

Though a shell may be a continuous or shape, the shell may be consideredto comprise a open shell and a closure (or a base shell and a lid). Theoverall dimensions of the solid dosage form are suitably definedentirely by the shell.

The shell composition suitably comprises one or more shell polymers,suitably pharmaceutical acceptable polymers (or GRAS approved polymers).The shell composition may comprise one or more thermoplastics. The shellcomposition may comprise one or more pharmaceutically acceptablepolymers selected from the group consisting of: (alkyl-)polyacrylates,silicones, polyurethanes, polyolefins (e.g. polystyrene), polyalkyleneglycols, polyvinyl alcohols, polyamides, acrylonitrile butadiene styrene(ABS), polylactic acid (PLA), polyglycolide, nylon, and/or co-polymersor mixtures thereof. The list is by no means exhaustive.

The shell filament (used in printing of shells) and shell filamentcomposition may be exactly as described in paragraphs [00331] to [00340]of WO2016/038356 (by the present applicant), which is incorporatedherein by reference. Such shell filament compositions may comprise oneor more of: shell polymers identical to those set forth in paragraph[00289] to [00302], fillers as set forth in paragraph [00303] to[00304], plasticizers as set forth in paragraph [00305] to [00312], andother ingredients as explained in paragraph [00313] to [00317] of thesame document. Moreover, the shell filament and shell filamentcomposition may be characterised as set forth in paragraph [00244] to[00270] to the extent that these paragraphs are applicable to the“further filament compositions” described in paragraph [00331] to[00340] of this document.

The shell filament, shell filament composition, and ultimate shellcomposition suitably comprise a meltable component. The shellcomposition may also comprise a non-meltable component to mitigatenozzle blockages. Suitably, the “meltable” component is a component thatmelts (or undergoes a glass transition to thereby soften) at thedesignated operating temperature of any corresponding 3D printerextrusion nozzle configured to process said filament, whereas the“non-meltable” component is suitably a component that does not melt (orundergo a glass transition) at the same temperature. Suitably, the“meltable” component may be a mixture of components, which collectivelymelt or undergo glass transitions together as a mixture—e.g. shellpolymer and plasticizers. However, “non-meltable” components are morelikely to be individual components with different melting points orglass transition temperatures. Suitably the meltable component has amelting point (or T_(g)) at or below 220° C., suitably at or below 150°C., suitably at or below 100° C., suitably at or below 80° C., suitablyat or below 60° C. Suitably the meltable component has a melting point(or T_(g)—i.e. at least one T_(g)) greater than or equal to 20° C.,suitably greater than or equal to 30° C., suitably between 30 and 65°C., suitably between 30 and 35° C. Suitably, the non-meltable componenthas a melting point (or T_(g)) at or above 150° C., suitably at or above200° C., suitably at or above 500° C., suitably at or above 1000° C.

As explained above, references to “meltable” and “non-meltable”components encompasses “softenable” and “non-softenable” componentsrespectively, where instead of “melting” at a particular temperature thecomponent “softens”. As such, references in this context to a meltingpoint may additionally or alternatively relate to a glass transitiontemperature. Such glass transitions are particularly applicable tothermoplastic component(s). As such, a “meltable” component may be athermoplastic component, suitably who glass transition temperature(temperature at which the thermoplastic component softens rather thanmelts) is lower than the temperature to which said component is exposed(e.g. during printing).

Each of the various filament ingredients described herein are suitablyeither a meltable or a non-meltable component (not both). For instance,a shell polymer is suitably a meltable component and is suitablyselected to undergo melting or a glass transition during printing. Afiller (e.g. calcium tribasic phosphate, talc, etc.), by contrast, issuitably a non-meltable component and is suitably selected so as toremain solid during printing. Notwithstanding the contrastingmelting/glass-transition properties of the various ingredients, suitablythe filament itself has a characteristic glass transition temperature.Suitably this characteristic glass transition temperature is measurableusing the well-known techniques described herein and elsewhere, and is aconsequence of the combination of ingredients. Various concentration (wt%) ratios of meltable:non-meltable components may afford viablefilaments for 3D printing. Suitably the ratio of meltable:non-meltablecomponents is between 1:10 and 10:1, more suitably between 3:7 and 7:3,suitably between 4:6 and 6:4, where suitably the meltable component(s)collectively include all relevant meltable components (e.g. shellpolymers, plasticizers, etc.) and the non-meltable component(s) includeall relevant non-meltable components (e.g. filler(s), lubricants, etc.).

The shell filament is suitably sufficiently stiff to enable it to beviably fed (at a consistent rate) to and through a correspondingextrusion nozzle within the printing apparatus or 3D printer. The activeshell filament is suitably sufficiently stiff to avoid the filamentbecoming stretched during printing. However, the filament is suitablynot so stiff that the nozzle operating temperature required to extrudethe filament will degrade the contents of the ingredient (e.g. causing achange in composition of greater than or equal to 1 wt %).

The shell filament is suitably sufficiently flexible and/or soft toenable it to be extruded (at a consistent rate) from a correspondingextrusion nozzle within the printing apparatus or 3D printer. The shellfilament is suitably sufficiently flexible and/or soft to allow thefilament to be viably spooled/coiled around a filament spool.

The shell filament is suitably neither too brittle (and breakable duringprinting/spooling) nor too flexible (precluding its viable conveyancethrough the printing apparatus or 3D printer). The shell filamentcomposition and dimensions (e.g. thickness) of the filament can bejudiciously altered, using the principles taught in the presentdisclosure, to obtain an optimal filament structure.

The shell filament suitably has a thickness (i.e. diameter or maximumthickness) of between 0.1 mm and 5 mm, suitably between 0.5 mm and 4 mm,more suitably between 1 mm and 3 mm, most suitably between 1.5 mm and 2mm. In a particular embodiment, the shell filament has a thickness ofabout 1.75 mm. However, the filament thickness may be adjusted to suitthe extrusion nozzles (in particular the size/diameter of the respectiveopenings thereof) through which they are to be extruded.

Suitably, the shell filament is capable of being coiled (or spooled)around a spool, suitably a spool having a hub diameter of about 20 cm,suitably a hub diameter of about 10 cm, suitably about 5 cm, suitablyabout 2.5 cm, suitably about 1 cm, suitably without breaking and/orstretching.

The shell filament suitably has a glass transition temperature (TObetween 20 and 200° C., suitably between 45° C. and 165° C., or suitablybetween −10° C. and 165° C.

Suitably, the shell filament is judiciously tailored with appropriateproportions and types of ingredients to produce filaments with a desiredT_(g) and/or melting point to minimise the corresponding nozzleoperating temperature required for extrusion.

The shell filament (and hence the shell composition) suitably comprisesa shell polymer. The shell polymer is suitably a meltable component orotherwise has the properties defined herein in relation to a meltablecomponent. The shell filament optionally comprises a plasticizer. Theshell filament optionally comprises a filler, where suitably said filleris a non-meltable component or otherwise has the properties definedherein in relation to a non-meltable component. In a particularembodiment, the shell filament comprises a shell polymer and aplasticizer. In a particular embodiment, the shell filament comprises ashell polymer and a filler (suitably that is non-meltable as definedherein). In a particular embodiment, the shell filament comprises ashell polymer, a plasticizer, and a filler.

Suitably, the shell filament of the invention comprises greater than orequal to 10 wt % shell polymer(s) (suitably excluding anyplasticizer(s)), suitably greater than or equal to 20 wt %, suitablygreater than or equal to 30 wt %, suitably greater than 50 wt %,suitably greater than or equal to 70 wt %, suitably greater than orequal to 79 wt %. Suitably, the shell filament of the inventioncomprises less than or equal to 99 wt % shell polymer(s) (suitablyexcluding any plasticizer(s)), suitably less than or equal to 95 wt %,suitably less than or equal to 90% wt, suitably less than or equal to 80wt %, suitably less than or equal to 60 wt %.

Suitably, the shell filament of the invention comprises greater than orequal to 0.1 wt % plasticizer(s), suitably greater than or equal to 1 wt%, suitably greater than or equal to 3 wt %, suitably greater than orequal to 4 wt %, suitably greater than 9 wt %, suitably greater than orequal to 15 wt %. Suitably, the shell filament of the inventioncomprises less than or equal to 50 wt % plasticizer(s), suitably lessthan or equal to 40 wt %, suitably less than or equal to 30 wt %,suitably less than or equal to 20 wt %, suitably less than or equal to11 wt %.

Suitably, the shell filament of the invention comprises greater than orequal to 1 wt % filler(s), suitably greater than or equal to 5 wt %,suitably greater than or equal to 10 wt %, suitably greater than 20 wt%, suitably greater than or equal to 30 wt %. Suitably, the shellfilament of the invention comprises less than or equal to 70 wt %filler(s), suitably less than or equal to 60 wt %, suitably less than orequal to 50 wt %, suitably less than or equal to 40 wt %, suitably lessthan or equal to 35 wt %.

In a particular embodiment, the shell filament (and thus the shellcomposition and/or shell filament composition) comprises or consists of:

10 to 90 wt % shell polymer(s);

and optionally:

1 to 30 wt % plasticizer(s); and/or

1 to 60 wt % filler(s).

In a particular embodiment, the shell filament (and thus the shellcomposition and/or shell filament composition) comprises or consists of:

30 to 80 wt % shell polymer(s);

and optionally:

5 to 20 wt % plasticizer(s); and/or

10 to 50 wt % filler(s).

In a particular embodiment, the shell filament (and thus the shellcomposition and/or shell filament composition) comprises or consists of:

40 to 60 wt % shell polymer(s);

and optionally:

10 to 20 wt % plasticizer(s); and/or

30 to 40 wt % filler(s).

In a particular embodiment, the shell filament (and thus the shellcomposition and/or shell filament composition) comprises or consists of:

40 to 60 wt % shell polymer(s);

10 to 20 wt % plasticizer(s); and

30 to 40 wt % filler(s).

Shell Polymer(s)

Any suitable polymer(s) may be used.

The melting point (or glass transition temperature) of the shell polymeris suitably less than the active ingredient, suitably by at least 20°C., more suitably by at least 40° C., more suitably by at least 50° C.The shell polymer suitably has a melting point between 140 and 250° C.,more suitably between 150 and 200° C., most suitably between 155 and175° C.

Suitably the shell polymer has a specific heat of between 0.1 and 1cal/g° C., most suitably between 0.3 and 0.5.

The shell polymer suitably has a density between 1.1 and 1.6 g/mL, mostsuitably between 1.2 and 1.4.

The shell polymer suitably has a glass transition temperature lower thanthe melting point of the active ingredient, suitably at least 20° C.lower, more suitably at least 40° C. lower, more suitably at least 50°C. lower.

The shell polymer(s), especially where an immediate release solid dosageform is desired, is suitably selected from a polymer (suitably acationic polymer or neutral polymer or copolymer) having a viscosity ofno more than 50 mPa·s, suitably no more than 30 mPa·s, suitably no morethan 10 mPa·s, though suitably having a viscosity of at least 1mPa·s—most suitably a viscosity between 2 and 8 mPa·s. The shellpolymer(s), especially where an immediate release solid dosage form isdesired, is suitably selected from a polymer having a molecular weightof at least 20,000 g/mol, more suitably at least 35,000, more suitablyat least 45,000, though suitably less than 1,000,000 g/mol, moresuitably less than 100,000 g/mol—most suitably a molecular weightbetween 35,000 and 65,000 g/mol. The shell polymer(s), especially wherean immediate release solid dosage form is desired, is suitably selectedfrom a polymer having a glass transition temperature (Tg) of at most100° C., suitably at most 80° C., suitably at most 50° C., thoughsuitably at least −10° C., more suitably at least 35° C.—most suitably aTg between 30 and 60° C. In some embodiments, the shell polymer(s) maynot have a glass transition temperature as such, though observedsoftening may still occur. The shell polymer(s), especially where animmediate release solid dosage form is desired, is suitably an(optionally alkyl-, suitably methyl- or ethyl-) acrylate, methacrylateand/or ethacrylate copolymer (suitably comprising amine-containingmonomeric units) suitably having a viscosity between 2 and 8 mPa.,suitably having a molecular weight between 35,000 and 65,000 g/mol,and/or suitably having a Tg between 30 and 60° C. In a particularembodiment, the relevant copolymer is poly(butylmethacrylate-co-(2-demethylaminoeethyl) methacrylate-co-methylmethacrylate), suitably in a respective monomeric molar ratio of 1:2:1(+/−5% for each molar value of the ratio). The shell polymer is suitablyEudragit E.

The shell polymer(s), especially where an extended release solid dosageform is desired, is suitably selected from a polymer having a viscosityof no more than 30 mPa·s, suitably no more than 20 mPa·s, suitably nomore than 16 mPa·s, though suitably having a viscosity of at least 1mPa·s—most suitably a viscosity between 1 and 15 mPa·s. The shellpolymer(s), especially where an extended release solid dosage form isdesired, is suitably selected from a polymer having a molecular weightof at least 10,000 g/mol, more suitably at least 250000, more suitablyat least 30,000, though suitably less than 100,000 g/mol, more suitablyless than 40,000 g/mol—most suitably a molecular weight between 29,000and 35,000 g/mol. The shell polymer(s), especially where an extendedrelease solid dosage form is desired, is suitably selected from apolymer having a glass transition temperature (Tg) of at most 100° C.,suitably at most 80° C., suitably at most 70° C., though suitably atleast 40° C., more suitably at least 50° C.—most suitably a Tg between55 and 70° C. In some embodiments, the shell polymer(s) may not have aglass transition temperature as such, though observed softening maystill occur. The shell polymer(s), especially where an extended releasesolid dosage form is desired, is suitably an (optionally alkyl-,suitably methyl- or ethyl-) acrylate, methacrylate and/or ethacrylatecopolymer (suitably comprising amine-containing monomeric units)suitably having a viscosity between 1 and 15 mPa., suitably having amolecular weight between between 29,000 and 35,000 g/mol, and/orsuitably having a Tg between 55 and 70° C. In a particular embodiment,the relevant copolymer is poly(ethyl acrylate-co-methylmethacrylate-co-trimethylammonioethyl methacrylate chloride), suitablyin a respective monomeric molar ratio of 1:2:0.2 (+/−5% for each molarvalue of the ratio). The shell polymer is suitably Eudragit RL.

The shell polymer(s), especially where a delayed release solid dosageform is desired, is suitably selected from a polymer having a viscosityof at least 20 mPa·s, suitably at least 40 mPa·s, suitably at least 50mPa·s, though suitably having a viscosity of no more tan 300 mPa·s,suitably no more than 210 mPa·s—most suitably a viscosity between 40 and210 mPa·s. The shell polymer(s), especially where a delayed releasesolid dosage form is desired, is suitably selected from a polymer havinga molecular weight of at least 10,000 g/mol, more suitably at least15,000, though suitably less than 400,000 g/mol—in a particularembodiment the molecular weight is between 10,000 and 25,000 g/mol,whereas in other embodiments the molecular weight is between 100,000 and350,000 g/mol. The shell polymer(s), especially where a delayed releasesolid dosage form is desired, is suitably selected from a polymer havinga glass transition temperature (Tg) of at least 80° C., suitably atleast 90° C., suitably at least 100° C., though suitably at most 200°C., more suitably at most 160° C.—most suitably a Tg between 90 and 160°C. In some embodiments, the shell polymer(s) may not have a glasstransition temperature as such, though observed softening may stilloccur. The shell polymer(s), especially where a delayed release soliddosage form is desired, is suitably selected from:

-   -   an (optionally alkyl-, suitably methyl- or ethyl-) acrylate,        methacrylate and/or ethacrylate polymer or copolymer (suitably        free of any amine-containing monomeric units), suitably with a        viscosity between 90 and 210 mPa·s, suitably with a molecular        weight between 100,000 and 350,000 g/mol, and/or suitably with a        glass transition temperature between 90 and 140° C.; wherein the        relevant polymer or copolymer is suitably selected from:        poly(methacylic acid-co-ethyl acrylate), suitably in a        respective monomeric molar ratio of 1:1 (+/−5% for each molar        value of the ratio); poly(methacylic acid-co-methyl        methacrylate), suitably in a respective monomeric molar ratio of        1:1 (+/−5% for each molar value of the ratio); poly(methacylic        acid-co-methyl methacrylate), suitably in a respective monomeric        molar ratio of 1:2 (+/−5% for each molar value of the ratio); or    -   a cellulose or cellulose derivative, suitably a hydroxypropyl        methylcellulose (HPMC) derivative, most suitably a hydroxypropyl        methylcellulose (HPMC) acetate succinate (HPMCAS), suitably with        a molecular weight between 10,000 and 25,000 g/mol and/or        suitably with a glass transition temperature between 100 and        145° C. (or suitably between 100 and 165° C.); wherein the        relevant HPMCAS is suitably selected from Aqoat LG, Aqoat MG,        and/or Aqoat HG. Suitably HPMC derivatives may, however, also        include hydroxypropylmethylcellulose phthalate (HPMCP), such as        HP-50, HP-55 and HP-55S grades thereof.

In principle any suitably polymer(s) may be used, including any one ormore of those selected from an (optionally alkyl-, suitably methyl- orethyl-) acrylate, methacrylate and/or ethacrylate copolymer (suitablycomprising amine-containing monomeric units); an (optionally alkyl-,suitably methyl- or ethyl-) acrylate, methacrylate and/or ethacrylatepolymer or copolymer (suitably free of any amine-containing monomericunits); a cellulose or cellulose derivative; polyvinyl alcohol (PVA);poly(lactic-co-glycolic acid) (PLGA); and/or any suitable pharmaceuticalacceptable carrier.

The shell polymer(s) is suitably selected from Eudragit E, Eudragit NE,HPC SSL, Eudragit RS, Eudragit RL, HPC SL, HPC M, HPC H, EudragitL100-55, Eudragit L100, Eudragit S100, Aqoat LG, Aqoat MG, Aqoat HG,and/or polyvinyl alcohol (PVA), or any combination of any of theaforementioned.

In some embodiments, especially where an active ingredient has limitedsolubility in a target solubilisation medium (e.g. in the body), shellpolymer(s) such as polyvinylpyrrolidone polymers orpolyvinylpyrrolidone-derived polymers may be employed. Such polymers canfacilitate dissolution of an active ingredient that may otherwiseexhibit limited solubility. In a particular embodiment, PVP K29-32 (apovidone) may be used. When present, suitably a PVP or PVP-based polymeris present (e.g. in a filament, solid dosage form, or core) at aconcentration of between 20 and 80 wt %, suitably at a concentrationbetween 40 and 60 wt %, suitably 45-55 wt %. PVP and PVP-based shellpolymers may be used alongside one or more filler(s), and optionallywith other ingredients such as plasticizer(s). Mixtures of different PVPor PVP-based polymers may also or alternatively be used (e.g. PVPs ofdifferent molecular weights).

In some embodiments, polyalkyleneglycol and polyalkyleneglycol-derivedpolymers may be employed as a shell polymer. In a particular embodimentthe polyalkyleneglycol or polyalkyleneglycol-derived shell polymer is apolyethyleneglycol (PEG) or polyethyleneglycol-derived shell polymer.Suitably, wherever a PEG or PEG-based shell polymer is deployed, atleast a portion of the PEG or PEG-based shell polymer has a molecularweight of at least 100,000, though suitably at most 1,000,000. However,a mixture of different polyalkyleneglycol and polyalkyleneglycol-derivedpolymers (e.g. PEG or PEG-based shell polymers) may be incorporatedwithin filaments and/or corresponding dosage forms. For instance, a highmolecular weight PEG may be used alongside a relatively low molecularweight PEG to achieve an optimal balance of properties. Higher molecularweight PEG and PEG-based polymers (e.g. M_(w)≥80,000) can serve aspolymer molecules, whereas lower molecular weight PEG and PEG-basedpolymers (e.g. M_(w) 200-20000) may serve as plasticizers and/orsolubility enhancers. Increasing the proportions of lower molecularweight PEGs is likely to lower the T_(g) of the resulting filament,Moreover, increasing the proportions of lower M_(w) PEGs also favoursaccelerated drug release. Suitably any PEG or PEG-based shell polymersare used alongside one or more filler(s), though such polymers may beused with or without non-melting components.

Plasticizer(s)

The shell filament (and hence shell composition) may suitably comprise aplasticizer. Such a plasticizer may improve the quality of filament(e.g. in terms of smoothness, flexibility, fluidity on extrusion). Theplasticizer may serve to lower the glass transition (or softening)temperature of the filament (or of the polymers), and consequent mayallow lower extrusion nozzle operating temperatures to be used duringprinting and/or formation of the filament.

In general, if a filament has a glass transition temp (Tg) that is toohigh, it may be too brittle (for instance, to coil onto a filamentspool) for an FFF 3D printer to handle (i.e. without breaking thefilament), and/or may require extrusion nozzle operating temperaturesthat are so high that degradation of the ingredients within the filamentmay occur. Where a filament has a glass transition temperature that istoo low, the filament may be too soft and/or flexible for an FFF 3Dprinter to handle, too distortable for consistent printing, and yieldspoor shape control and incoherent solid dosage form products. Aplasticizer can be used as an additive to optimise the performance of afilament by obtaining the optimal glass transition or softeningtemperature and striking the right balance of properties.

The filament may comprise any suitable plasticizer. Manypharmaceutically acceptable plasticizers are known in the art for use inthe formation of pharmaceutical solid dosage forms.

In a particular embodiment, the plasticizer may be selected from one ormore of triethylcitrate (TEC), glycerol, castor oil, oleic acid,glycerol, tryacetin and polyalkylene glycols (e.g. a polyethylene glycolor polypropylene glycol, such as PEG400).

Certain plasticizers may be more appropriate than others, depending onthe particular active ingredient and shell polymer(s). Particularcombinations that offer excellent performance include:

-   -   TEC and/or triacetin (0.5-10 wt % thereof within the filament as        a whole) plasticizer in conjunction with cellulose-based        polymers, such as HPC, HPMC, and HPMCAS;    -   glycerol plasticizer in conjunction with PVA-based polymer;    -   TEC plasticizer (suitably 0.5-30 wt % thereof within the        filament as a whole) in conjunction with (optionally alkyl-,        suitably methyl- or ethyl-) acrylate, methacrylate and/or        ethacrylate polymer or copolymers.

More than one plasticizer (optionally as defined herein) may be used.

In an alternative embodiment, instead of incorporating the plasticizerwithin the filament, the plasticizer may be coated upon the surface ofthe relevant filament, suitably so as to provide the requiredmalleability and viable nozzle operating temperature. In a particularembodiment, during the printing process a filament (with or without aplasticizer therein) may be conveyed towards a corresponding extrusionnozzle via a plasticizer dispenser which coats the surface (or a partthereof) of said filament with the plasticizer. As such, in a particularembodiment, the shell filament may suitably comprise or be contactedwith a plasticizer before it is extruded from a corresponding extrusionnozzle.

Filler(s)

As aforementioned mentioned, suitably shell filaments of the inventioncomprise one or more filler(s), suitably in the amounts stated. Suitablyfiller(s) are included alongside shell polymer(s) such as thosedescribed herein, and optionally also along with other excipients suchas plasticizer(s), binders, and the like. Achieving an ideal balancebetween the respective ingredients is possible by following theteachings of the present specification. Typically, the inclusion of oneor more filler(s) within a filament or filament composition willstrengthen the resulting filaments and thereby facilitate theirgeneration and processing during 3D printing. However, too muchfiller(s) may lead to a degree of brittleness, which can be mitigatedthrough the judicious use of other ingredients (e.g. plasticizers andthe like that may serve to soften the filaments), by lowering theproportions of filler, and/or changing the nature of the filler (e.g.its melting point).

Numerous fillers are known in the art of pharmaceuticals andnutraceuticals, and any of these may be deployed where appropriate ordesired for a particular drug or nutraceutical formulation. Suitably, atleast one (preferably all) of the filler(s) have a melting pointexceeding the relevant operating temperature(s) of components with whichthe filaments make contact (e.g. printing nozzles, extrusion nozzles,and/or heated conveyors or feeders). Suitably, the filler(s) aresubstantially inert, and/or suitably have minimal or no interaction withother component(s) of the filament or dosage form, for instance a drugor polymer. Talc is an ideal filler for use in the filaments and dosageforms of the present invention, especially in conjunction with PVP orPEG polymers.

Other Ingredients

The shell filament may contain one or more other ingredients. Otheringredients may suitably include one or more excipients, excipientcarriers, and/or diluents, all of which may be included in shellfilament.

In particular, the one or more other ingredients within the printingfilament may be selected from one or more fillers/diluents,antiadherants, binders, disintegrants, lubricants, glidants,flavourants, preservatives, sweeteners, and coatings.

Suitable antiadherants may include magnesium stearate. Suitablediluents/fillers may include plant cellulose, dibasic calcium phosphate,vegetable fats and oils, lactose, sucrose, glucose, mannitol, sorbitol,calcium carbonate, magnesium stearate, and/or microcrystallinecellulose. Suitable binders may include saccharides;polysaccharides/derivatives thereof, for example, starches, cellulose ormodified cellulose such as microcrystalline cellulose and celluloseethers such as hydroxypropyl cellulose, hydroxypropyl methyl cellulose,and derivatives thereof; sugar alcohols, for example, xylitol, sorbitolor maltitol; synthetic polymers, for example, polyvinylpyrrolidone(PVP), polyethylene glycol (PEG) . . . ). Suitable disintegrants mayinclude crosslinked polyvinylpyrrolidone (crospovidone), crosslinkedsodium carboxymethyl cellulose, croscarmellose sodium, modified starchsodium and/or starch glycolate. Suitable lubricants may include silica;fats, e.g. vegetable stearin; magnesium stearate or stearic acid; and/ortalc. Suitable glidants may include fumed silica, talc, magnesiumcarbonate, and/or colloidal silica. Suitable coatings may include tabletcoatings to protect tablet ingredients from deterioration by moisture inthe air and make large or unpleasant-tasting tablets easier to swallow(e.g. a cellulose ether hydroxypropyl methylcellulose (HPMC) filmcoating; synthetic polymers, shellac, corn protein zein or otherpolysaccharides, gelatin; enteric coatings, for example, including fattyacid(s), wax(es), shellac, plastics, plant fibres). The generic classesof excipients are well understood by those skilled in the art.

In particular embodiments, the shell filament comprises talc (which issuitably a filler as mentioned above). Talc may serve as non-meltingparticles which improve the performance of the extrusion nozzle. Afilament or a final solid dosage form (or a core thereof) may comprisebetween 10 and 50 wt % talc, 40 wt %, since too much lubricant may leadto poor adhesion of the solid dosage form to the build platform duringprinting.

Such excipients may be chosen to suit the properties of the final soliddosage form, the properties of a filament, or both, or a judiciouscompromise between both. For instance, in terms of the solid dosageform, excipient(s) may be chosen for ease of administration to thetarget patient population(s) by the intended route; improved dosingcompliance; consistency and control of drug bioavailability; to enablebioavailability; improved active ingredient stability includingprotection from degradation; to ensure a robust and reproduciblephysical product. In terms of a filament (e.g. for use in FFF 3Dprinting), excipient(s) may be chosen to optimise the physical formand/or stability of the filament; to ensure a robust and reproduciblephysical products; flexibility and rigidity of the filament (an optimalbalance between flexibility and rigidity of a filament is desirable toensure that the filament can be conveyed successfully to an extrusionnozzle but then easily extruded from the nozzle); to enable productionof optimal solid dosage forms (e.g. as per the aforementioned points).

Filament Coating

Filaments may suitably comprise a protective filament coating, suitablycoated upon the outermost surface of said filament. Such filamentcoatings may be deployed regardless of whether single-head or multi-head(e.g. dual-head) printing is used, though such coatings are perhaps mostapplicable in multi-head printing scenarios where filaments are atincreased risk of prolonged exposure to heat (and consequential filamentdegradation) whilst temporarily at rest (when not being printed) withintheir corresponding nozzles.

The protective filament coating(s) are suitably derived fromcorresponding protective filament coating compositions. Suitably theprotective filament coating comprises pharmaceutically and/ornutraceutically acceptable ingredients. Suitably the protective filamentcoating us a liquid or oil, suitably having a high boiling point (e.g.at least 150° C., suitably at least 170° C., suitably at least 220° C.).The coating suitably reduces degradation of the filament upon exposureto heat. The protective filament coating (or composition) suitablycomprises a liquid and/or oil. Suitably the protective coating does notprevent the relevant filament from melting or undergoing a glasstransition at the operating temperature of the extrusion nozzle.

The inventors found that the use of olive oil BP, oleic acid,arachidonic acid and glycerol helps co-ordination between the two-nozzleand to evade drug-polymer filament degradation. Using such components tocoat a filament is thought to provide a protective layer on the surfaceof the filament. Such components also have relatively high meltingpoints and do not degrade at the processing temperature of the 3Dnozzle.

Core

The core is suitably a non-printed composition. The core is suitablybulk dispensed (e.g. a pre-determined volume or mass thereof dispensedto a specific target location) and is suitably not characterised by alayered structure.

The core comprises or consists of a core composition. The corecomposition is unprintable via the structured printing nozzle throughwhich the shell may be printed. The core composition suitably comprisesone or more active ingredients. The core composition may be any suitablepharmaceutical, nutraceutical, or food supplement, composition, thoughmost preferably the core composition is a pharmaceutical composition.Suitably the core composition is a pharmaceutical composition comprisingat least one active and one or more pharmaceutically acceptableexcipients or carriers. The core composition may be any knownpharmaceutical composition, be it in a liquid or solid particulate form.However, the pharmaceutical composition may consist or essentiallyconsist of the active ingredient(s).

Suitably the active ingredient is thermosensitive. Suitably the activeingredient is susceptible to decomposition at or above 200° C., suitablyat or above 150° C., suitably at or above 100° C., suitably at or above60° C. Such decomposition is suitably discernible by techniques known inthe art, for example, DSC.

The core composition suitably is or comprises a liquid, a solid, or agelled composition.

A liquid core composition may be a suspension (including ananosuspension), emulsion, dispersion (including colloidal dispersion),etc. and may thus comprise particulate solids. Alternatively a liquidcore composition may be a solution comprising the active ingredient.

A solid core composition is suitably a particulate solid composition.Particulate solids may include powders, granules, and pellets, thoughmost suitably a solid particulate core composition comprises or consistsof a powder or granules. Other forms of particulate solids that may beused are minitablets, crystals, cubes, etc.

The average particle size of the solid particulate core composition maysuitably be greater than or equal to 10 nm, suitably greater than orequal to 100 nm, suitably greater than or equal to 1 μm, suitablygreater than or equal to 10 μm, suitably greater than or equal to 100μm, suitably greater than or equal to 200 μm. The average particle sizeof the solid particulate core composition may suitably be less than orequal to 1000 μm, suitably less than or equal to 500 μm, suitably lessthan or equal to 400 μm, suitably less than or equal to 100 μm, suitablyless than or equal to 1 μm. In a particular embodiment the averageparticle size of the solid particulate core composition is between 1 and10 μm. In a particular embodiment, the average particle size of thesolid particulate core composition is between 50 μm and 300 μm, suitablybetween 60 μm and 250 μm, more suitably between 70 μm and 200 μm, mostsuitably between 80 μm and 190 μm.

A solid core composition may thus be a “bound” or “unbound” particulatesolid. Though dispensed as a particulate solid, after dispensing a corecomposition may become or be otherwise transformed into a solidmonolithic core within the shell into which the core is received. Suchtransformations to a monolithic core may be caused by the addition of abinder (e.g. where a further core composition precursor(s) orreactant(s) is used) or other such agent that may cause particles tobind together to form a “bound” particulate solid. In some embodiments,the solid core composition is an unbound particulate solid within theshell.

An advantage of the core-shell arrangement afforded by methods of theinvention is that it permits high loadings of active ingredients in thecore. As such, the core or core composition may comprise the one or moreactive ingredients at a concentration greater than or equal to 1 wt %,suitably greater than or equal to 10 wt %, suitably greater than orequal to 30 wt %, suitably greater than or equal to 50 wt %, suitablygreater than or equal to 80 wt %.

Packaging of Solid Dosage Forms

Solid dosage form(s) of the invention may be packaged by any one of anumber of methods well known in the art. Where, for example,pharmaceutical solid dosage forms according to the invention areproduced via printing apparatus situated in a pharmacy (e.g. to providea patient with customised medicaments on-demand), the pharmacist maypackage the solid dosage forms in a number of ways, including in tabletbottles, or even monitored dosing systems which may be subsequentlydispatched to hospitals, care homes, and the like for ultimatedispensation to a patient.

In some embodiments, the packaging may be formed by the same or adifferent printing apparatus. In some examples, the packaging and soliddosage forms may be produced simultaneously, whereby the printingoperation utilises one or more filament(s) pertaining to the soliddosage form, and one or more filament(s) pertaining to the packaging,and the packaging may be built around the solid dosage form(s) duringprinting.

Preparing Shell Filaments

A shell filament is suitably prepared by any one of the methodsdescribed in WO2016/038356 (by the present applicant).

EXAMPLES

The present invention will now be further described by way of thefollowing non-limiting examples. In particular the Examples demonstratethat by printing a partial shell, dispensing a solid or a liquidthereinto, and closing the shell, one can viably produce a wide range ofsolid dosage forms. It will be understood, therefore, that the presentinvention is in no way limited to the specific exemplified compositionsor equipment described, and that the concepts are broadly applicable toa host of embodiments.

Apparatus

Two types of basic apparatus for printing shells and dispensing coresmay be as set forth in FIG. 1.

FIG. 1 is a schematic diagram of a dual FDM 3D printer adapted toaccommodate a) a liquid dispenser or b) a powder/granule/pelletsdispenser in combination with FDM 3D printer head.

FIG. 1(a) depicts a fused filament fabrication (FFF) 3D printer that hasbeen adapted. The printer has one FFF printing nozzle (i.e. a structuralshell printing nozzle), equipped with a nozzle, movable extruder, gears,and other standard 3D printing-nozzle components; a syringe (i.e.non-structural core dispenser) which replaces a second FFF printingnozzle previously installed within the printer; and a build platform.The apparatus is operable, via a computer, to print an open shell (asdepicted on the building place) with a shell printing filament thatpasses through the FFF printing nozzle, and to thereafter fill the emptyopen shell with a liquid core composition dispensed from the syringe.The “filled shell” may then be closed with further shell printingfilament that can be printed onto the top of the “filled shell”.

FIG. 1(b) depicts the same apparatus as per FIG. 1(a) except that theliquid-dispensing syringe is replaced by a hopper equipped with anelectronically-operated lower valve (i.e. tap). Such an apparatus isoperable in like manner to that of FIG. 1(a), except that instead ofdispensing liquid, particulate solids charged into the hopper aredispensed through the electrically operated lower valve into the openshell, before the filled shell is subsequently closed in the same manneras set for in relation to FIG. 1(a).

The aforementioned apparatuses were essentially formed from a dual head3D printer that was modified by replacing a second FDM printing headwith either i) an extrusion head (a syringe pressure controller based onopen source design) or ii) in house built powder dispenser.

FIG. 2 shows a dual FDM 3D printer adapted to accommodate a liquiddispenser in combination with FDM 3D printer head and furtherillustrates, by way connecting arrows between an image of a basiccore-shell structure and the relevant print, which components areconfigured to print each part of a core-shell structure.

Example 1—Preparation of Dipyridamole Solution (Core Composition)

A model drug, dipyridamole, was chosen to test the suitability of thissystem to provide immediate and extended drug release. Its fluorescecolour and ease of detection allows focusing on the development process.Initially dipyridamole solution with different solvent systems wasoptimised as shown in Table 1. It was decided that the drug solution PEG400 (10 mg/ml) is the maximum concentration that can be readilyprepared.

TABLE 1 optimization of highly concentrated dipyridamole solution forliquid capsule feed. Concentration Formulation (mg/ml) ResultDipyridamole + water 20 Slightly soluble Dipyridamole + 20 Slightlysoluble ethanol:water (20:80) Dipyridamole + Peg 400 20 Not completedissolved Dipyridamole + Peg 5 Soluble 400:Ethanol Dipyridamole + Peg400 10 Soluble

Example 2—Preparation of the Shell Filament (Shell Composition)

In order to engineer the shell, a methacrylic polymer with entericproperties (pH threshold >5.5), was utilized. Eudragit L 100-55, TEC andtalc was used in the ratio 50:16.66:33.33 respectively. A physicalmixture was extruded using HME at 135° C. feeding temperature and 125°C. extruding temperature. The nozzle size was 1 mm to allow theexpansion of the filament to approximately 1.65 mm after extrusion.Similar procedures for preparing suitable printing filaments areoutlined in the Examples of WO2016/038356.

Example 3—Dosing Accuracy of the Liquid Extruder

In order to assess the accuracy of the dosing the weight of dispensedsolution following the order to fill a constant shape was assess in sixreplications (Table 2).

TABLE 2 reproducibility test for the liquid dispenser head ExtrusionWeight of solution (g) speed (mm/s) (mm/s) 1 2 3 4 5 6 Average STDEV %SD 20 0.0750 0.0729 0.0723 0.0830 0.1217 0.0973 0.0870 0.0194 22.3097

Example 4—3D Printing of Entire Liquid Capsule

3D printing of a liquid capsule was performed using theliquid-dispensing apparatus described above and illustratedschematically in FIG. 1(a)—i.e. using a dual FDM 3D printer with one ofthe printing heads replaced with a liquid or semi-solid extruder. Thedipyridamole solution was loaded into the extruder and the filament intothe regular FDM head.

FIG. 3 shows a portion of the dual FDM 3D printer adapted to accommodatea liquid dispenser (right) in combination with FDM 3D printer head(left).

TABLE 3 3D Printing parameters for both shell filaments and dispensingof the core 3D printing parameters core Shell Nozzle temperature (° C.)0 185 Platform temperature (° C.) 40 Extrusion speed (mm/s) 20 Nozzlesize (mm) 0.4 0.41

TABLE 4 Tablet dimensions for the shell and the liquid core X (mm) Y(mm) Z (mm) Core 8.00 3.16 1.50 shell 18.38 8.00 7.45

TABLE 5 The positions of the shell and the core during liquid capsuleprinting process X (mm) Y (mm) Z (mm) Core −101.11 −45.07 3.50 shell−101.11 −45.07 0.00

Example 5—In Vitro Dissolution Test

The in vitro dissolution studies was carried out manually in a USP IIdissolution tester. Samples were taken at 15 mins interval for 4 hrs.This was filtered through a 0.2 μm filter and analysed using HPLC. ThepH of the media was from 1.2 to 6.8 after 2 hrs by adding sodiumtribasic phosphate buffer.

HPLC Parameters

Agilent technologies 1200 series HPLC system was also used in thedipyridamole analysis. Randomly selected tablets were placed in a 500 mlvolumetric flask containing 250 ml of HPLC water. This was sonicated for2 hours before adding 250 ml of acetonitrile and further sonicated for30 mins, cooled and filtered before analysis. The HPLC system consistsof XTerra RP 18 4.6×150 mm, 5 μm column (made in Ireland) which wasmaintained at 40° C. The mobile phase was comprised of phosphate bufferpH 6.8 and acetonitrile (60:40) at a flow rate of 1 ml/min. Theinjection volume was 10 μl and the maximum run time for the assay was 10mins. 282 nm was the assay wavelength.

FIG. 4 is a graph showing a time-course in vitro drug release profilefor of dipyridamole release from Eudragit L based capsules filled withdrug suspension. It was possible to control drug release during theacidic phase of the experiment (2 hours). Following pH change, the modeldrug started to be released after 30 min, indicating the proof ofconcept of crafting an enteric soft capsule based on this technology.

It was decided that it is possible to include more drug contents byemploying a drug suspension rather than drug solution. In the next step,a dipyridamole suspension was used in the liquid dispenser so higherdrug concentration can be employed in the system.

Example 6—Preparation of Dipyridamole Suspension as a Feed Solution forLiquid Dispenser

Dipyridamole 1500 mg was suspended in distilled water (5%) and sonicatedfor 10 mins. This was then milled using Ultra Turrax Homogeniser at25000 rpm for 1 hr. Methocel E4 (0.5%) was added to the sample and thenprobe sonicated at 15 mins interval in an ice bath for 1 hr. The size ofmicro-particles were investigated using Mastersizer.

NB: Methocel E4 was added after size reduction using Ultra Turrax toreduce foam production

The use of PVP as a suspending agent produced larger particles.

TABLE 6 Size reduction, homogenisation, and general preparationconditions Size reduction technique Time (mins) Size (μm) SPANHomogenisation 60 9.461 3.193 Probe sonication 60 5.877 2.013

The reduction of particle size to less than 6 micron significantlyretards the sedimentation rate of the drug. It is anticipated thatemploying nano-suspensions may allow for even better accuracy.

Example 7—Dosing Accuracy and Relationship Between the TheoreticalVolume and Actual Volume for Single and Dual FDM Printing

This was carried out using a theoretical cube shape as the object withthe dimensions as stated bellow. This was to be able to relate thetheoretical volume to the actual volume obtained from using differentnozzle sizes (0.25, 0.41 and 0.84 mm).

TABLE 7 the theoretical volume of cube object that was used to controlthe liquid dispenser. Cube dimension (mm) Theoretical vol (mm³)Theoretical vol (ml) 6.21 240 0.24 5.85 200 0.2 5.43 160 0.16 4.93 1200.12 4.31 80 0.08 3.42 40 0.04 2.71 20 0.02 2.15 10 0.01

In order to establish the link between theoretical volume and thepractical suspension volume that was dispensed a number of calibrationcurves with different nozzle sizes were plotted.

It is clear that it is possible to control the volume dispensed bycontrolling the theoretical volume of dispensed liquid in the printersoftware (FIG. 5). This was achieved across the 3 different nozzledispenser. It is also noted that the linearity is maintained when dualprinting is employed (FIG. 6). However the dispensed volume slightlydropped when dual printing was employed (FIG. 7). This might be relatedto the changes in the pressure applied to the syringe duringco-ordination with the FDM printer's head.

FIG. 5 shows a calibration curve for the actual volume againsttheoretical volume for single head printing using (a) 0.25, (b) 0.41 or(c) 0.84 mm nozzle sizes. This proves the possibility of controlling thedose with different nozzle sizes

FIG. 6 shows a calibration curve for actual volume against theoreticalvolume for dual printing head using (a) 0.25, (b) 0.41 or (c) 0.84 mmnozzle size.

FIG. 7 shows the relationship between actual volumes from single anddual printing from (a) 0.25, (b) 0.41 or (c) 0.84 mm nozzle.

Example 8—Example of Controlling the Dose 3D Printing of the LiquidCapsule

The optimized liquid suspension was used as a feed to fabricate a 3Dprinted enteric capsule In this example, a capsule for enteric liquidcapsule containing a suspension of dipyridamole. Three different dosesof the dipyridamole was tried.

The enteric shell was prepared using Eudragit L55-100 and as detailedpreviously in section. The printing parameter is detailed in Table 5.

TABLE 8 Printing parameters for dual 3D printing of enteric capsule 3Dprinting parameters core Shell Nozzle temperature (° C.) 0 185 Platformtemperature (° C.) 40 Extrusion speed (mm/s) 20 Nozzle size (mm) 0.40.41

TABLE 9 The dimensions of the core of the tablet has been modified toencapsulate a different volume (dose) of the drug Volume (μl) X (mm) Y(mm) Z (mm) Core 30 7.5 2 2 45 7.5 3 2 60 705 4 2 shell 18.38 8.00 7.45

It was also necessary to position the core (liquid) in an elevatedposition to allow the formation of the shell with a wall of‘significant’ heights in order to contain the poured liquid (Table 8).

TABLE 10 the positioning of the shell and the core of the capsule X (mm)Y (mm) Z (mm) Core −101.11 −45.07 2.50 shell −101.11 −45.07 0.00

Example 9—In Vitro Release Studies UV Spectrophotometric Analysis

The in vitro dissolution studies was carried out using a USP IIdissolution tester. Samples were taken automatically at 5 mins intervaland analyse for below detailed HPLC. The pH of the media was from 1.2 to6.8 after 2 hrs by adding sodium tribasic phosphate buffer.

HPLC Analysis

Agilent technologies 1200 series HPLC system was also used in thedipyridamole analysis. Randomly selected tablets were placed in a 500 mlvolumetric flask containing 250 ml of HPLC water. This was sonicated for2 hours before adding 250 ml of acetonitrile and further sonicated for30 mins, cooled and filtered before analysis. The HPLC system consistsof XTerra RP 18 4.6×150 mm, 5 μm column (made in Ireland) which wasmaintained at 40° C. The mobile phase was comprised of phosphate bufferpH 6.8 and acetonitrile (60:40) at a flow rate of 1 ml/min. Theinjection volume was 10 μl and the maximum run time for the assay was 10mins. 282 nm was the assay wavelength.

FIG. 8 shows in vitro release of dipyridamole from Eudragit L basedcapsule filled with drug suspension with different loading. It waspossible to maintain grastric resistant properties with no drug releasein the acid and extended release in gastric media pH. This exampleprovides a proof of concept of fabricating an enteric polymer withpotential of controlling dose to suit a particular patient.

Example 10—3D Printing of Immediate Release Liquid Capsule

In order to prove the possibility of crafting immediate release liquidcapsule using this technology, the capsule was crafted using the samedipyridamole suspension but with filament made of immediate releasepolymer (Eudragit E), the polymer is highly soluble in the acidicmedium.

A mixture (10 g) consisting of 45% Eudragit E po, 5% triethyl citrateand 50% talc was physically mixed before feeding into a hot meltextruder at 100° C. This was allowed to mix for 5 min before extrudingat 90° C. 1.5 mm nozzle was used on the extruder and extrusion was doneusing torque of 0.4 N.

Preparation of dipyridamole suspension (as stated in previous example)

TABLE 11 Printing parameters for dual 3D printing of immediate releasecapsule 3D printing parameters core Shell Nozzle temperature (° C.) 0135 Platform temperature (° C.) 40 Extrusion speed (mm/s) 90 Nozzle size(mm) 0.25 0.4

TABLE 12 The dimensions of the core of the tablet has been modified toencapsulate a different volume (dose) of the drug Volume (μl) X (mm) Y(mm) Z (mm) Core 15 7.5 1 2 30 7.5 2 2 45 7.5 3 2 Shell (1.2 mm thick)19.59 9.20 8.65

TABLE 13 the positioning of the shell and the core of the capsule X (mm)Y (mm) Z (mm) Core −101.11 −45.07 2.50 shell −101.11 −45.07 0.00

FIG. 9 shows the release profile of dipyridamole from immediate releaseshell. It is clear that 100% drug release is achieved within 15 min ofintroduction to the acidic media, hence complying with pharmacopeialcriteria for immediate release capsules. It was also possible to controlthe drug dose of the drug by modifying the volume of the dispensedvolume through the printer software scale's command.

FURTHER EXAMPLES Example 11—Example of Liquid Capsule Containing aControlled Dose of a Drug Suspension

In this example, immediate release capsules were produced. The capsuleswere filled with a suspension of a model drug, dipyridamole. Usingcomputer aided software it was possible to control the dose ofdipyridamole by controlling the volume dispensed using different designsfor the core.

Preparation of Shell Filament

For the preparation of the shell, API-free Eudragit EPO or RL filamentswere produced by a HAAKE MiniCTW hot melt compounder (Thermo Scientific,Karlsruhe, Germany). An optimised ratio of a powder mixture containing athe polymer, plasticizer (TEC) and filler (talc) was gradually added tothe HME and allowed to mix for 5 min at 80 rpm to allow homogenousdistribution of the molten mass. Afterwards, the filament was extrudedat 20 rpm. The processing parameters for the hot melt extrusion areshown in Table 14.

Preparation of the Liquid Core

Two liquid model cores (aqueous active solution or suspension) wereprepared to be used in the syringe dispenser:

Dipyridamole suspension was initially prepared by sonicating 1.5 g/30 mLof aqueous dipyridamole suspension. Size reduction was achieved byinitial application of T8.01 Ultra Turrax Homogeniser (IKA, Germany) at25,000 rpm. This was carried out for 1 h at 15 min interval with 5 mincooling time between the intervals. Methocel E4 (0.5% w/v) was added tothe suspension before probe sonicating using Sonics Vira cell (USA) at15 min interval in an ice bath for additional 4 h using an amplitude of70%. The final suspension we diluted with Methocel E4 (0.5% w/v) toachieve a drug concentration of 1.50 w/v. The size distribution ofdipyridamole particles in the suspension were confirmed by using aMastersizer 2000 laser diffractomer (Malvern Instruments, UK).

Modification of Dual FDM 3D Printing

In order to make the manufacturing of the liquid capsule fullyautomated, a Makerbot replicator Experimental 2× dual FDM 3D printer(MakerBot Industries, New York, USA) was modified to dispense liquids.The right extruder of the 3D printer was replaced with a syringe-basedliquid dispenser as shown in FIG. 1. The design for the paste extruderwas obtained from an open source website and was 3D printed using an M2Makergear FDM 3D printer (MakerGear, LLC, Ohio, US).

Liquid Capsule Design and Printing

The shells were designed as a 1.6 mm thick capsule with differentdimensions as shown in Table 15. As the liquid core will be dispensedand will take the shape of the cavity of the shell, the core of thetablet was designed as a cube to simplify controlling dispensed volumeby changes the cube volume. For the fabrication of liquid capsule, twodifferent printing modes were employed:

a. Single-phase printing: In Makerbot Desktop software (MakerBotIndustries, New York, USA), the core was placed in the centre of thecavity of its corresponding shell and was printed by the interchangingprinting of the shell filament and core liquid.

b. Multi-phase printing: In Simplify3D software, the shell was designedto comprise a complementary bottom and a cap. This liquid capsuleprinting was done in three phases: i) printing of the bottom, ii)filling of the liquid and iii) sealing of the bottom in a separate 3Dprinting stage.

The liquid capsules for both modes were printed with cube dimensionscorresponding to 80, 120, 240 or 320 μL (Table 15). The settings of thesoftware were modified and the parameters of 3D printing of the shellwere printed as shown in Table 14. The resolution was set at medium (200μm layer thickness), the infill was 100% and the internal and externalinfill pattern were set at Grid and Concentric respectively. The outlineoverlap was set at 90% and the rest of the setting were default. Thescript of the software was also modified to prevent priming of theliquid dispenser to reduce waste and as priming was not necessary forliquids.

FIG. 10 shows a rendered image and photograph of a liquid capsule madeof an immediate release shell (Eudragit E shell) and filled withmicrosuspension of dipyridamole (1.5% w/v).

TABLE 14 Shell filament formulations with their HME and 3D printindprocessind parameters 3D Processing Extrusion Nozzle printing PlatformPolymer TEC Talc temp temp size temp temp (%) (%) (%) (° C.) (° C.) (mm)(° C.) (° C.) Eudragit EPO 45 5 50 100 90 1.7 135 40 Eudragit RL 45 5 50130 120 1.7 170 20 Eudragit 50 16.67 33.33 135 125 1 185 40 L100-55

TABLE 15 Theoretical volume dimensions, of core and shell and wight, ofestimated and actual dose Theoritical Core's Dimensions Shell'sDimensions Estimated Estimated Actual Volume (mm) (mm) Weight VolumeDose dose Sample (μL) x y z x y z (mg) (μL) (mg) (mg) Core 1  80 4.324.32 4.32 23 10.35 6.74 82.25 ± 6.95  78.33 ± 6.62  1.18 ± 0.10 1.51 ±0.17 Core 2 160 5.43 5.43 5.43 23 10.35 6.74 185.83 ± 23.75  176.98 ±22.62  2.65 ± 0.34 3.11 ± 0.17 Core 3 240 6.22 6.22 6.22 23 10.35 7.74284.55 ± 1.48   271 ± 1.41 4.07 ± 0.02 4.99 ± 0.49 Core 4 320 6.84 6.846.84 23 10.35 9.74 385.73 ± 30.57  367.36 ± 29.11  5.51 ± 0.44 6.60 ±0.86

In Vitro Dissolution Test

In vitro drug release studies for all liquid capsules used in this studywere carried out in triplicate in a suitable dissolution media at37±0.5° C. with a paddle speed of 50 rpm.

Eudragit EPO-dipyridamole liquid capsule release studies wasinvestigated using an Erweka DT 600 dissolution tester (USP II). Themedia used was 900 mL of 0.1 M HCl. Four mL aliquots were manuallycollected using 5 mL Leur-Lok syringes at 0, 5, 10, 15, 20, 25, 30, 40and 60 min time intervals and filtered through a Millex-HA 0.45-μmfilter. Each aliquot withdrawn was replaced with 4 mL of 0.1 M HCl.These where analysed using HPLC methods reported in section 2.11.

FIG. 11 is a chart showing the impact of single and alternating printingmodes from the liquid dispenser using a 2 mL syringe.

FIG. 12 is a chart showing the impact of single and alternating printingmodes from the liquid dispenser using a 10 mL syringe.

FIG. 13 is a graph showing the linear relationship between theoreticalvolumes calculated volumes based on volume of design and the actual doseachieved via 3D printing.

FIG. 14 shows in vitro immediate release profiles for dypiridamolesuspension from 3D printed liquid Eudragit EPO capsule using USP II withdifferent core volumes in gastric media (pH 1.2).

The above experiments demonstrate the possibility to control liquiddoses within capsules based on an immediate release shell and a liquidsuspension. Doses can be easily modified through merely changing thedispensed volume. Though both single-phase and multi-phase printingmodels allowed adequate control of dose, the bi/multi-phasal modelafforded less troubleshooting and gave a higher success rate.

Example 12—Experiments with Different Shell Printing Methods

The same capsule design (Eudragit E) as per Example 11 were filled withdipyridamole suspension. During capsule shell printing two printingmodes were tested.

FIG. 15 shows SEM images of the top of shell produced by two differentfilling modes: a) concentric Filing and b) rectangular filling.

Capsules formed via concentric filling were much more effective thanrectangular-filling designs in controlling liquid contents andpreventing leakage.

Example 13—Example Liquid Capsules Containing Drug Solutions in BothImmediate Release and Extended Release Shells

In this example, the core composition is a drug solution (rather than adrug suspension as per previous examples) and it is shown to be suitablein both immediate release and extended release systems.

The capsules were prepared as per Example 11, with shell materials shownin Table 14. Eudragit RL was used for extended release shells.

Theophylline solution was prepared by adding 15 g of citric acid and 1.5g of Tween 80 to a 4% w/v theophylline aqueous suspension (50 mL). Thiswas heated to 65° C. and stirred until a complete solution is formed.Methocel E4 was then added to achieve a Methocel solution concentrationof 0.25% w/v before cooling in an ice bath.

In Vitro Dissolution Test

Eudragit EPO-theophylline liquid capsule release studies was conductedusing an AT 7 Smart dissolution USP II apparatus (Sotax, Switzerland)equipped with in-line UV/VIS spectrophotometer (PG Instruments Limited,UK). The media used was 900 mL of 0.1 M HCl. The amount of releasedtheophylline was determined at 5 min intervals by at a wavelength of 272nm and path length of 1 mm. Data was analysed using IDISis software(Automated Lab, 2012). For Eudragit RL 100-Theophylline liquid capsules,the test were carried out using 750 mL of a stimulated gastric fluid(0.1 M HCl, pH 1.2) for 2 hrs followed by 12 h exposure to pH 6.8phosphate buffer. This was carried out using AT 7 Smart dissolution USPII apparatus.

FIG. 16 shows release profiles for theophylline-cored-capsules producedwith immediate release shells containing Eudragit EPO.

FIG. 17 shows release profiles for theophylline-cored-capsules producedwith extended release shells containing Eudragit RL 100.

This example demonstrates the possibility of producing liquid capsulescontaining a drug solution, and also demonstrates the flexibility of theinvention to afford immediate and extended release patterns.

Example 14—Example Capsules Containing Granules

In this example we demonstrate the ability of modified FDM 3D printer toproduce a capsule whilst a secondary nozzle equipped with Clench Valveto control granule flow. The clench valve could be opened and closed ina coordinate fashion to allow filling of the capsule. Theophyllinegranules (25%) were prepared as a model powder. The shell of the capsulewere made of Eudragit E and Eudragit L100-55 for immediate and delayedrelease respectively.

Modification of Hyrel SDS Clench Valve Head

A funnel was attached to a flexible tube and installed on a clench valveto replace the need for a syringe head since powder flow will be due togravity. A nozzle was attached to the other end of the tube for moreprecise dispensing. This was then linked to an SDS head from Hyrel 3DM30 modular 3D printer (Hyrel 3D, GA, US) to control dispensing.

Preparation of Theophylline Granules

Theophylline (250 g), lactose monohydrate (240 g), PVP K90 (10 g) andapproximately 30 ml of water was mixing using a planetary mixer forabout 15 min. Granulation was carried out manually using a 1 mm sievesize and the product was dried in an oven at 70° C. until no weight lossdue to moisture was observed. The final product was passed through a 1mm sieve and large granules were size reduced. Size distributionexperiment was carried out on the granules using sieve sizes of 710,500, 315, 250, 180 and 90 μm.

Optimisation of Granule Sizes for Powder Dispensing

The different granule size ranges were fed into the funnel. Powder flowwas due to gravity which was then control by the clench valve.

Three sets of granules of the following size were used: 710-1000 μm,500-710 μm and 315-500 μm due to the internal diameter of the tube usedwas blocking flow. 315-180 μm size range had a similar issue but to alesser degree. The following size range (180-90 μm) produced the bestflow and control using the clench valve.

Dispensing Accuracy of the Powder Dispenser

Granule sizes 180-90 μm was fed into the powder dispenser and a solidobject with dimensions at shown in Table 16 was chosen as the printedobject. The volume of the object was varied and the powder dispensed wascollected and weight. The calibration curve was plotted.

TABLE 16 dimensions of square object design, volume and correspondingcapsule volume following 3D printing process Capsule Dimensions (mm)Volume Core mass core no X Y Z (mm³) (mg ± SD) 1 5 7.5 0.2 7.5 1718.5 ±109 2 5 5 0.2 5 1122.8 ± 74  3 5 2.5 0.2 2.5 563.3 ± 65 4 5 1.25 0.21.25  322 ± 23

FIG. 18 shows a calibration curve for the powder dispenser (pinchvalve).

Preparation of Filaments for FDM 3D Printing

Eudragit EPO or Eudragit L100-55 was mixed with triethyl citrate andtalc (45:5:50) before feeding it into the hot melt extruder at 100° C.and 130° C. respectively. This was mixed for about 5 min beforeextrusion at 10° C. below the feeding temperatures. A 1.7 mm nozzle wasused during extrusion.

3D Printing of Capsules

The 3D printing of the capsule was carried out using a Hyrel system 30Mwith multiple heads for 3D printing. One of the heats was fitted with aFDM head and the other was the modified head for powder dispenser. Amultiple phase printing mode was utilised in the printing were thebottom of the capsule was printed before the powder filling and eventualsealing of the capsule. The shell printing was carried out at 135° C.and 170° C. for Eudragit EPO and L100-55. The powder dispensing wascarried out at room temperature.

In Vitro Release Studies

This was carried out using USP II dissolution tester. The paddlerotation was at 50 rpm and the temperature of the 0.1N HCL dissolutionmedia set at 37° C. For the Eudragit RL 100 based capsule, the media pHwas changed to 6.8 after 2 hrs and then to 7.4 after 6 hrs.

FIG. 19 shows an in vitro dissolution profile, in gastric medium (0.1 MHCl) USP II dissolution test, for an immediate release 3D printedcapsule filled with theophylline granules.

FIG. 20 shows an in vitro dissolution profile, in gastric medium (0.1 MHCl), of 3D printed delayed release entire capsule filled withtheophylline granules.

1. An apparatus for preparing (or printing) a solid dosage form, theapparatus comprising: a 3D printer; and a build platform upon which thesolid dosage form is printable; and a computer for controlling the 3Dprinter and optionally also the build platform; wherein the apparatuscomprises or is otherwise associated with: a structural printing nozzlefor printing a pre-defined three-dimensional shell, comprising a shellcomposition, onto the build platform; and a non-structural dispenser forunstructured dispensing of a core composition into the shell; whereinthe non-structural dispenser is either unheated or is otherwiseassociated with a temperature control element configured to maintain thetemperature of the non-structural dispenser (and suitably also itscontents) at a temperature at or below 60° C.
 2. (canceled)
 3. Theapparatus as claimed in claim 1, wherein the apparatus is operable undercomputer control to coordinate metered dispensing of each dose of corecomposition (or precursor thereof) with the printing of shellcomposition.
 4. The apparatus as claimed in claim 3, wherein thenon-structural dispenser is configured for dispensing particulatesolids; and
 5. (canceled)
 6. The apparatus as claimed in claim 3,wherein the non-structural dispenser is configured for dispensingliquids (suitably including suspensions, emulsions, dispersions); andthe non-structural dispenser comprises a syringe operable to dispense ametered quantity of liquid.
 7. (canceled)
 8. The apparatus as claimed inclaim 1, wherein the structural printing nozzle and the non-structuraldispenser are both incorporated within the 3D printer.
 9. (canceled) 10.(canceled)
 11. The apparatus as claimed in claim 1, wherein the 3Dprinter is a fused filament fabrication (FFF) 3D printer, and: thenon-structural dispenser is operable to dispense liquids and/orparticulate solids in a metered fashion at a temperature at or below 60°C.; and the structural printing nozzle is configured for printing ashell printing filament comprising the shell composition (or a precursorthereof) at temperatures between 60 and 350° C.
 12. A method ofpreparing a solid dosage form comprising a core and a three-dimensionalshell surrounding the core, the method comprising: printing onto a buildplatform, via a structural printing nozzle, the three-dimensional shell,which three-dimensional shell comprises a shell composition (orprecursor thereof); and dispensing into the three-dimensional shell, viaa non-structural dispenser, a core composition (or precursor thereof),wherein the non-structural dispenser is either unheated or is otherwiseassociated with a temperature control element configured to maintain thetemperature of the non-structural dispenser (and suitably also itscontents) at a temperature at or below 60° C.
 13. The method ofpreparing a solid dosage form as claimed in claim 12, the methodcomprising: printing a pre-defined three-dimensional open shell,comprising a shell composition (or precursor thereof), onto a buildplatform; dispensing a core composition (or precursor thereof) into theopen shell to produce an open core-containing shell; closing the opencore-containing shell by printing a closure thereupon.
 14. (canceled)15. (canceled)
 16. The method of claim 12, wherein the core composition(or precursor thereof) is or comprises a liquid and/or particulate solidand is dispensed into the shell in a metered fashion at a temperature ator below 60° C.; and the shell is printed with a shell printingfilament, comprising the shell composition (or a precursor thereof), viaa fused filament fabrication printing nozzle (i.e. a structural printingnozzle) operating at a temperature between 60 and 350° C.
 17. (canceled)18. A solid dosage form obtainable by the method as claimed in claim 12.19. A solid dosage form comprising a core and a three-dimensional3D-printed shell surrounding the core; wherein: the shell comprises ashell composition comprising (or formed from) a 3D printing composition;and the core comprises a core composition comprising a pharmaceutically,nutraceutically, or food-supplement active ingredient, wherein the corecomposition is contained by the shell; optionally wherein the soliddosage form is obtainable by the method as claimed in claim
 12. 20. Thesolid dosage form of claim 19, wherein shell has a 3D-printed layerstructure whereas the core has a non-layered structure.
 21. The soliddosage form of claim 19, wherein the core is physically detached fromthe shell and physically movable therein in the presence of freeinternal space.
 22. The solid dosage form of claim 19, wherein the corecomposition is a pharmaceutical composition comprising at least onepharmaceutical active and one or more pharmaceutically acceptableexcipients or carriers.
 23. The solid dosage form of claim 22, whereinthe at least one pharmaceutical active is or comprises a thermosensitivebiopharmaceutical.
 24. The solid dosage form of claim 19, wherein thecore composition is a particulate solid composition with an averageparticle size greater than or equal to 10 nm and less than or equal to1000 μm.
 25. The solid dosage form of claim 19, wherein the corecomposition is a liquid composition, optionally comprising someparticulate matter (e.g. as per a suspension, emulsion, dispersion). 26.The solid dosage form of claim 19, wherein the shell compositioncomprises a 3D-printed shell filament (i.e. a filament for fusedfilament fabrication).
 27. The solid dosage form of claim 19, whereinthe shell comprises one or more shell polymers having a glass transitiontemperature (T_(g)) greater than or equal to 30° C. and less than orequal to 100° C.
 28. The solid dosage form of claim 27, wherein theshell comprises or consists of: 10 to 90 wt % shell polymer(s); andoptionally: 1 to 30 wt % plasticizer(s); and/or 1 to 60 wt % filler(s).29. (canceled)